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White Paper

EMC STORAGE DESIGN AND DATA PROTECTION FOR VMWARE ZIMBRA COLLABORATION SERVER VMware Zimbra Collaboration Suite 7.2, VMware vSphere 5, and EMC VNX series storage • Efficient storage configuration based on EMC’s building-block sizing approach • Instant snapshot-based backup and recovery with EMC Replication Manager and EMC VNX SnapView • Simplified high availability with VMware HA clustering

EMC Solutions Group Abstract This white paper describes how to design an enterprise email solution based on VMware® Zimbra® Collaboration Server™ (ZCS), VMware vSphere™ 5, and EMC® VNX™ Series storage. This solution offers a high-performing, efficient, and predictable storage design with full availability and protection by leveraging the features and strengths of EMC VNX series storage, EMC VNX SnapView™ and EMC Replication Manager for snapshot-based backup and recovery, and VMware vSphere 5 for high availability. July 2012

Copyright © 2012 EMC Corporation. All Rights Reserved. EMC believes the information in this publication is accurate as of its publication date. The information is subject to change without notice. The information in this publication is provided “as is.” EMC Corporation makes no representations or warranties of any kind with respect to the information in this publication, and specifically disclaims implied warranties of merchantability or fitness for a particular purpose. Use, copying, and distribution of any EMC software described in this publication requires an applicable software license. For the most up-to-date listing of EMC product names, see EMC Corporation Trademarks on EMC.com. VMware, ESX, VMware vCenter, and VMware vSphere are registered trademarks or trademarks of VMware, Inc. in the United States and/or other jurisdictions. All trademarks used herein are the property of their respective owners. Part Number H10866.1

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Table of contents Executive summary............................................................................................................................... 6 Business case .................................................................................................................................. 6 Efficiently size and provision storage........................................................................................... 6 Ensure continuous availability..................................................................................................... 6 Ensure nondisruptive backup and near-instantaneous recovery .................................................. 6 Solution overview ............................................................................................................................ 7 Key findings ..................................................................................................................................... 7 Introduction.......................................................................................................................................... 8 Purpose ........................................................................................................................................... 8 Scope .............................................................................................................................................. 8 Not in scope..................................................................................................................................... 8 Audience ......................................................................................................................................... 8 Technology overview ............................................................................................................................ 9 Overview .......................................................................................................................................... 9 VMware Zimbra Collaboration Server ............................................................................................... 9 VMware vSphere .............................................................................................................................. 9 EMC VNX series storage ................................................................................................................... 9 EMC VNX5700 storage array ........................................................................................................... 10 EMC SnapView ............................................................................................................................... 10 EMC Navisphere Admsnap ............................................................................................................. 10 EMC Replication Manager .............................................................................................................. 11 EMC PowerPath/VE ........................................................................................................................ 11 EMC Virtual Storage Integrator (VSI) plug-in for vSphere ................................................................. 11 VMware ZCS architecture ................................................................................................................... 12 Core advantages ............................................................................................................................ 12 Zimbra packages ........................................................................................................................... 12 Zimbra Core............................................................................................................................... 12 Zimbra LDAP.............................................................................................................................. 12 Zimbra Store (Zimbra server) ..................................................................................................... 13 Zimbra MTA ............................................................................................................................... 13 Zimbra SNMP ............................................................................................................................ 13 Zimbra Logger ........................................................................................................................... 13 Zimbra Convertd ........................................................................................................................ 13 Zimbra Spell .............................................................................................................................. 13 Zimbra Proxy ............................................................................................................................. 13 Zimbra Memcached ................................................................................................................... 13 Zimbra Archiving ....................................................................................................................... 13 EMC STORAGE DESIGN AND DATA PROTECTION FOR VMWARE ZIMBRA COLLABORATION SERVER VMware Zimbra Collaboration Suite 7.2, VMware vSphere 5, and EMC VNX Series storage

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Zimbra mailbox server architecture .................................................................................................... 14 Disk layout ..................................................................................................................................... 14 Solution architecture and design........................................................................................................ 15 Target ZCS mail user profile............................................................................................................ 15 Architecture overview ..................................................................................................................... 15 Architecture diagram...................................................................................................................... 16 Hardware components ................................................................................................................... 17 Software ........................................................................................................................................ 17 VMware vSphere design ..................................................................................................................... 18 DRS affinity rules............................................................................................................................ 18 Storage sizing and configuration........................................................................................................ 20 Mailbox server building block design methodology ........................................................................ 20 Building block design .................................................................................................................... 20 Phase 1: Collect the requirements ............................................................................................. 20 Phase 2: Design the mailbox server building block .................................................................... 21 Phase 3: Deploy the building block and validate its design ....................................................... 21 Storage design considerations for Zimbra mailbox servers ................................................................ 22 ZCS I/O characteristics................................................................................................................... 22 ZCS mailbox server partitions......................................................................................................... 23 Mount points ................................................................................................................................. 23 Message stores .............................................................................................................................. 24 Redo logs ....................................................................................................................................... 24 ZCS mailbox server building block specifications ........................................................................... 25 Scaling to 10,000 users ................................................................................................................. 25 Mailbox server disk layout ............................................................................................................. 25 Storage provisioning with the VSI plug-in .......................................................................................... 27 Storage provisioning process with the VSI plug-in .......................................................................... 28 Notes ........................................................................................................................................ 30 EMC VSI Storage Viewer plug-in ..................................................................................................... 31 Configuration guidelines and best practices ...................................................................................... 32 VNX storage configuration recommendations................................................................................. 32 vSphere ESXi host configuration recommendations ....................................................................... 33 Guest virtual machine configuration recommendations.................................................................. 33 Linux filesystem alignment ........................................................................................................ 33 Linux filesystem alignment on very large LUNs .......................................................................... 34 Filesystem formatting ................................................................................................................ 34

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Protection (backup and recovery) configuration ................................................................................. 35 Preparing ZCS virtual machines for Replication Manager/SnapView snapshots ......................... 35 Special consideration for Linux filesystems.................................................................................... 36 Backup process with Replication Manager ..................................................................................... 37 Recovery process ........................................................................................................................... 39 Performance validation and test results ............................................................................................. 41 Disclaimer...................................................................................................................................... 41 Testing methods ............................................................................................................................ 41 Zimbra Soapgen test tool .......................................................................................................... 41 Test scenarios ................................................................................................................................ 42 Key performance indicators............................................................................................................ 43 Test 1 results: ZCS mailbox server building block performance .......................................................... 44 Test 2 results: ZCS mailbox server building block scalability ............................................................. 47 Test 3 results: Advanced protection for ZCS data using Replication Manager with VNX SnapView snapshots .......................................................................................................................................... 49 Snapshot space calculations ..................................................................................................... 49 Test 4 results: Benefits of using EMC VNX FAST Cache with ZCS data ................................................. 51 Test 5 results: Performance of NL-SAS disks with ZCS data ................................................................ 53 Conclusion ......................................................................................................................................... 54 Easy scaling with EMC’s building-block approach to sizing ............................................................ 54 Benefits of EMC VNX series FAST Cache.......................................................................................... 54 NL-SAS disk performance with ZCS ................................................................................................ 54 VMware HA clustering .................................................................................................................... 54 Advanced protection (backup and recovery) .................................................................................. 55 References.......................................................................................................................................... 56 White papers ................................................................................................................................. 56 Product documentation.................................................................................................................. 56 Appendix A: Example ZCS mailbox server storage space calculation .................................................. 57 Appendix B: Zimbra deployment worksheet ....................................................................................... 58

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Executive summary Business case

Today’s full-featured and robust enterprise collaboration platforms, such as VMware® Zimbra® Collaboration Server™ (ZCS), run best on an economical world-class storage system, such as the EMC® VNX™ series, designed to deliver maximum performance and scalability for mid-tier enterprises and optimized for virtual applications. It is essential to guarantee access to information for all end users, all the time, while also making the same information available to IT for backup, recovery, reporting, and testing. Efficiently size and provision storage Sizing and configuring storage for use with enterprise collaboration platforms can be a complicated process, driven by many variables and requirements, which vary from organization to organization. Properly configured storage, combined with optimally sized server and network infrastructures, can guarantee smooth enterprise collaboration operation. One of the methods that can be used to simplify the sizing and configuration of large amounts of VNX series storage for ZCS is to define a unit of measure—a mailbox server building block 1. Ensure continuous availability A highly available infrastructure, such as VMware High Availability clustering and VMware Distributed Resource Scheduling, provides uniform high availability across the entire virtualized IT environment without the cost and complexity of failover solutions tied to either operating systems or specific applications. Ensure nondisruptive backup and near-instantaneous recovery Disk-based replicas, made possible with products such as EMC SnapView™ and EMC Replication Manager, address the information access problem by using point-in-time copies, enabling parallel access to the desired resource in physical and virtual environments. These point-in-time replicas can be leveraged for backup acceleration, reporting, and testing with no impact to production, thus eliminating the need to prioritize access and increasing operational efficiency.

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A mailbox server building block represents the amount of storage and server resources required to support a specific number of ZCS users. The amount of required resources is derived from a specific user profile type, mailbox size, and disk requirements. Using the building block approach simplifies the design and implementation of ZCS. Once the initial building block is designed, it can be easily reproduced to support the required number of users in your enterprise. By using this approach, EMC customers can now create their own building blocks that are based on their company’s specific email environment requirements. This approach is very helpful when future growth is expected because it makes email environment expansion simple and straightforward. EMC best practices involving the building block approach for storage design have proven to be very successful in many customer implementations.

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Solution overview

ZCS is a complete, open source email and collaboration platform. It features email, contacts, calendar, documents, file sharing, tasks, and social media, plus synchronization for desktops and devices. VNX series storage provides a high-performance, unified storage platform with unsurpassed simplicity and efficiency, optimized for virtual applications. With the VNX series, you can achieve new levels of performance, protection, compliance, and ease of management. Instant snapshot-based backup and recovery is provided by Replication Manager and SnapView. Replication Manager automates the creation of snapshots of ZCS mailbox server volumes using SnapView technology. The combination of ZCS with VNX series storage provides an optimal collaboration infrastructure. Storage, compute, and network layers maintain high availability, while EMC’s building-block sizing approach achieves predictable performance and a repeatable storage design. In addition, EMC’s building-block approach to sizing accelerates your deployment of ZCS. Once deployed, the performance, management, and protection advantages of running ZCS on VNX series storage are self-evident. VMware HA provides uniform high availability across the entire virtualized IT environment without the cost and complexity of failover solutions tied to either operating systems or specific applications.

Key findings

Key aspects of this solution include: •

Full support for VMware vSphere™ 5.0 virtualization with all of vSphere’s advanced features



VNX storage is an excellent platform to house ZCS



Efficient storage configuration and scalability based on EMC’s building-block sizing approach 

Building block based on 5,000 heavy users per mailbox server validated



Simplified high availability with VMware High Availability (HA) clustering and Distributed Resource Scheduling (DRS)



Simple, effective, and quick storage provisioning for VMware Zimbra content with EMC VSI plug-in for VMware vCenter™



Instant snapshot-based backup and recovery with Replication Manager and SnapView



VNX series FAST™ Cache accelerates performance to address unanticipated workload spikes

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Introduction Purpose

The purpose of this white paper is to describe the design and validation of an enterprise email solution, based on VMware ZCS that offers a high-performing, efficient, and predictable storage design with full availability and protection. The paper describes how the solution leverages the features and strengths of EMC VNX series storage, EMC VNX SnapView, and EMC Replication Manager for snapshotbased backup and recovery, and VMware vSphere 5 for high availability.

Scope

The scope of this paper corresponds to the scope of the solution validation (build, test, and document) activities performed by EMC engineers in an EMC solutions laboratory. What was built and tested is described and, where possible, recommendations and guidelines are provided for professionals to design a similar solution. The concepts, instructions, procedures, recommendations, and guidelines presented in this document are thorough but not all-inclusive.

Not in scope

Neither installation/configuration instructions for ZCS nor detailed application architecture guidelines fall within the scope of this white paper.

Audience

The target audience for this white paper is business executives, IT directors, and infrastructure administrators who are responsible for their company’s messaging infrastructure. The target audience also includes professional services groups, system integration partners, and EMC teams tasked with deploying messaging systems in a customer environment. A high-level understanding of ZCS and VNX series storage is beneficial. Familiarity with VMware virtualization concepts is also beneficial.

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Technology overview Overview

VMware Zimbra Collaboration Server

This section provides an overview of the primary technologies used in this solution. The tight integration of these products and technologies yields all of the benefits of the enterprise messaging solution described in this paper. •

VMware Zimbra Collaboration Server (ZCS)



VMware vSphere



EMC VNX5700 storage system



EMC Replication Manager



EMC SnapView



EMC Navisphere® Admsnap



EMC PowerPath®/VE

ZCS is a next generation email, calendar and collaboration solution that is optimized for VMware. ZCS provides an open platform designed for virtualization and portability across private and public clouds, making it simpler to manage and more costeffective to scale. With the most innovative Web application available, ZCS boosts end-user productivity on any device or desktop—any time, any place—at dramatically lower costs compared to other providers. Versions of ZCS include a Network Edition, an Open-source Edition, and a prepackaged Virtual Appliance. This solution uses ZCS Network Edition and focuses on ZCS mailbox server design.

VMware vSphere

VMware vSphere uses the power of virtualization to transform data centers into simplified cloud computing infrastructures and enables IT organizations to deliver flexible and reliable IT services. vSphere virtualizes and aggregates the underlying physical hardware resources across multiple systems and provides pools of virtual resources to the data center. As a cloud operating system, vSphere manages large collections of infrastructure (such as CPUs, storage, and networking) as a seamless and dynamic operating environment and also manages the complexity of a data center.

EMC VNX series storage

EMC VNX series storage is powered by Intel® Xeon® Processors, for intelligent storage that automatically and efficiently scales in performance, while ensuring data integrity and security. The VNX series is designed to deliver maximum performance and scalability for mid-tier enterprises, enabling them to grow, share, and cost-effectively manage multiprotocol file and block systems. VNX arrays incorporate the RecoverPoint splitter, which supports unified file and block replication for local data protection and disaster recovery. EMC Unisphere® is the central management platform for the EMC VNX series, providing a single combined view of file and block systems, with all features and functions available through a common interface. Unisphere is optimized for virtual applications and provides industry-leading VMware integration, automatically discovering virtual machines and VMware ESXi™ servers and providing end-to-end, virtual-to-physical mapping.

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EMC VNX5700 storage array

The EMC VNX5700 storage array used in this solution is designed to deliver maximum performance and scalability for enterprises. It is a converged platform that replaces EMC CLARiiON® and EMC Celerra® and enables organizations to dynamically grow, share, and cost-effectively manage multiprotocol file systems and multiprotocol block storage access. The VNX Operating Environment enables Microsoft Windows and Linux/Unix clients to share files in multiprotocol (NFS and CIFS) environments. At the same time, it supports iSCSI, Fibre Channel (FC), and FCoE access for high-bandwidth and latency-sensitive block applications. For additional VNX specifications, refer to the EMC VNX Series Unified Storage Systems Specification Sheet.

EMC SnapView

EMC SnapView is a storage system-based software application that enables you to create a copy of a LUN by using either clones or snapshots. A clone is an actual copy of a LUN and takes time to create, depending on the size of the source LUN. A snapshot is a virtual point-in-time copy of a LUN and takes only seconds to create. SnapView has the following important benefits: •

It allows full access to a point-in-time copy of your production data with modest impact on performance and without modifying the actual production data.



For decision support or revision testing, it provides a coherent, readable, and writable copy of real production data.



For backup, it practically eliminates the time that production data spends offline or in hot backup mode, and it offloads the backup overhead from the production server to another server.



It enables you to maintain a consistent replica across a set of LUNs. You do this by performing a consistent fracture, which is a fracture of more than one clone at the same time, or a fracture that you create when starting a session in consistent mode.



It provides instantaneous data recovery if the source LUN becomes corrupt. You can perform a recovery operation on a clone by initiating a reverse synchronization on a snapshot session and by initiating a rollback operation.

Depending on your application needs, you can create clones, snapshots, or snapshots of clones. This solution uses EMC SnapView snapshots to protect ZCS mailbox server volumes. EMC Navisphere Admsnap

The EMC Navisphere Admsnap program runs on host systems in conjunction with SnapView running on the EMC VNX storage processors (SPs), and lets you start, activate, deactivate, and stop SnapView sessions. All Admsnap commands are sent to the storage system through the Fibre Channel bus. The Admsnap utility is an executable program that you can run interactively or with a script.

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EMC Replication Manager

EMC Replication Manager manages EMC point-in-time replication technologies through a centralized management console. Replication Manager coordinates the entire data replication process—from discovery and configuration to the management of multiple, application-consistent, disk-based replicas. Replication Manager is used to safeguard and protect your business-critical applications, such as Oracle, Microsoft Exchange Server, Microsoft SQL Server, and VMware-based virtual machines. In this solution, Replication Manager automates the creation of snapshots of ZCS mailbox server volumes using SnapView technology.

EMC PowerPath/VE EMC PowerPath/VE provides intelligent, high-performance path management with path failover and load balancing optimized for EMC and selected third-party storage systems. PowerPath/VE supports multiple paths between a vSphere host and an external storage device. Having multiple paths enables the vSphere host to access a storage device even if a specific path is unavailable. Multiple paths can also share the I/O traffic to a storage device. PowerPath/VE is particularly beneficial in highly available environments because it can prevent operational interruptions and downtime. The PowerPath/VE path failover capability avoids host failure by maintaining uninterrupted application support on the host in the event of a path failure (if another path is available). PowerPath/VE works with VMware ESX/ESXi as a multipath plug-in (MPP) that provides path management to hosts. It is installed as a kernel module on the vSphere host. It plugs into the vSphere I/O stack framework to provide the advanced multipathing capabilities of PowerPath/VE, including dynamic load balancing and automatic failover to the vSphere hosts. For this solution, PowerPath/VE is installed on all ESXi hosts that house ZCS virtual machines. EMC Virtual Storage Integrator (VSI) plug-in for vSphere

EMC Virtual Storage Integrator (VSI) for VMware vSphere is a free plug-in for VMware vSphere Client that provides a single management interface for managing EMC storage within the vSphere environment. Features can be added and removed from VSI independently, providing flexibility for customizing VSI user environments. Features are managed by using the VSI Feature Manager. VSI provides a unified user experience, allowing each of the features to be updated independently and new features to be introduced rapidly in response to changing customer requirements.

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VMware ZCS architecture VMware ZCS is designed to provide an end-to-end mail solution that is scalable and highly reliable. The messaging architecture is built with well-known open-system technology and standards and is composed of a mail server application and a client interface. Core advantages

Zimbra packages

The architecture includes the following core advantages: •

Open source integrations: Linux, Jetty, Postfix, MySQL, OpenLDAP



Uses industry standard open protocols: SMTP, LMTP, SOAP, XML, IMAP, POP2



Modern technology design: Java, JavaScript thin client, DHTML



Horizontal and vertical scalability: 

Each mailbox server can be scaled horizontally by adding more data stores



Each mailbox server can be scaled vertically by adding more CPU and memory resources to the virtual machines and by using advanced storage array technologies such as thin provisioning



High availability support: For cluster integration to provide high availability, ZCS can use either Linux clustering or VMware HA clustering 3



Browser based client interface: Zimbra Web Client gives users easy access to all the ZCS features



Administration console to manage accounts and servers

VMware ZCS includes the following application packages. For more information about each package, visit http://www.zimbra.com. Zimbra Core The Zimbra Core package includes the libraries, utilities, monitoring tools, and basic configuration files. Zimbra LDAP ZCS uses the OpenLDAP software, an open source LDAP directory server. User authentication is provided through OpenLDAP. Each account on the Zimbra Store server has a unique mailbox ID that is the primary point of reference to identify the account. The OpenLDAP schema has been customized for ZCS.

2

This solution focuses on the performance of ZCS with the most popular ZCS web client protocol, SOAP.

3

For high availability, this solution uses VMware HA clustering.

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Zimbra Store (Zimbra server) The Zimbra Store includes the components for the mailbox server, including Jetty, which is the servlet container the Zimbra software runs within. The Zimbra mailbox server includes the following components: •

Data store—The data store is a MySQL database



Message store—The message store is where all email messages and file attachments reside



Index store—Index and search technology is provided through Lucene; index files are maintained for each mailbox

Zimbra MTA Postfix is the open source mail transfer agent (MTA) that receives email via SMTP and routes each message to the appropriate Zimbra mailbox server using Local Mail Transfer Protocol (LMTP). The Zimbra MTA also includes the anti-virus and anti-spam components. Zimbra SNMP Installing the Zimbra SNMP package is optional. If you choose to install Zimbra SNMP for monitoring, run the package on every Zimbra server. Zimbra Logger Installing the Zimbra Logger package is optional. It can be installed on one mailbox server. The Zimbra logger installs tools for syslog aggregation and reporting. If you do not install the logger, the server statistics section of the administration console will not display. Zimbra Convertd The Zimbra Convertd package is installed on the Zimbra Store server. Only one Zimbra Convertd package needs to be present in the ZCS environment. Zimbra Spell Installing the Zimbra Spell package is optional. Aspell is the open source spell checker used on the Zimbra Web Client. When Zimbra Spell is installed, the Zimbra Apache package is also installed. Zimbra Proxy Installing the Zimbra Proxy is optional. Use of an IMAP/POP proxy server allows mail retrieval for a domain to be split across multiple Zimbra servers on a per user basis. The Zimbra Proxy package can be installed with the Zimbra LDAP, the Zimbra MTA, the Zimbra mailbox server, or on its own server. Zimbra Memcached Memcached is a separate package from Zimbra Proxy and is automatically selected when the Zimbra Proxy package is installed. One server must run Zimbra Memcached when the proxy is in use. All installed Zimbra proxies can use a single memcached server. Zimbra Archiving The Zimbra Archiving and Discovery feature is an optional feature for Zimbra Network Edition. Archiving and Discovery offers the ability to store and search all messages that were delivered to or sent by Zimbra. This package includes the cross-mailbox search function, which can be used for both live and archive mailbox searches. Using Archiving and Discovery can trigger additional mailbox license usage. EMC STORAGE DESIGN AND DATA PROTECTION FOR VMWARE ZIMBRA COLLABORATION SERVER VMware Zimbra Collaboration Suite 7.2, VMware vSphere 5, and EMC VNX Series storage

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Zimbra mailbox server architecture The Zimbra mailbox server is a dedicated server that manages all of the mailbox content, including messages, contacts, calendar, briefcase files, and attachments. Messages are received from the Zimbra MTA server and are then passed through any filters that have been created. Messages are then indexed and deposited into the correct mailbox. In addition to content management, the Zimbra mailbox server has dedicated volumes for backup and log files. Each Zimbra mailbox server in the system can see only its own storage volumes. Zimbra mailbox servers cannot see, read, or write to another server. In a ZCS single-server environment, all services are on one server, and during installation the computer is configured to partition the disk to accommodate each of the services. In a ZCS multi-server environment, the LDAP and MTA services can be installed on separate servers. Disk layout

The mailbox server includes the following volumes: •

Message Store (blob store)—Mail message files are located in opt/zimbra/store



Data Store—The MySQL database files are located in opt/zimbra/db



Index Store—Index files are located in opt/zimbra/index



Backup area—Full and incremental backups are located in opt/zimbra/backup



Log files—Each component in ZCS has log files. Local logs are located in /opt/zimbra/log

Additional information about mailbox server design is provided in the Storage design considerations for Zimbra mailbox servers section.

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Solution architecture and design Target ZCS mail user profile

The solution was validated with the ZCS mail user profile characteristics presented in Table 1. Table 1.

Target ZCS user profile characteristics

User profile characteristic

Value

Total users

10,000

Zimbra mailbox servers

2

Users per mailbox server

5,000

User mailbox size

500 MB

User workload message profile

Heavy Enterprise

Message profile characteristics

21 received/hour/user, 7 sent/hour/user (224 messages/user/8 hour day) 124 KB average message size 80% with 25 KB message body 20% with 20 KB message body and 500 KB attachment

Architecture overview

User type

90% SOAP 4 users, 10% IMAP users

Concurrency

100%

Read/write ratio based on profile and workload type

40% reads/60% writes

Mail stores per server

1

Blob message store LUN size

3.5 TB per server

To validate the performance and functionality of ZCS on EMC VNX series storage, we configured two VMware vSphere ESXi servers (nodes) on a VMware vSphere hypervisor platform and deployed multiple ZCS roles on each ESXi node. Two nodes were configured for VMware high availability (HA) and VMware Distributed Resource Scheduling (DRS) to achieve high availability and balanced performance. We configured each ESXi host with sufficient resources to support an entire 10,000-user ZCS environment. In the event of a vSphere cluster node failure, or during vSphere cluster node maintenance, all virtual machines on the affected node were configured to move automatically to the still-functioning node.

4

SOAP: Simple Object Access Protocol, an XML-based messaging protocol used for sending requests for Web services. The Zimbra servers use SOAP for receiving and processing requests, which can come from Zimbra command line tools or Zimbra user interfaces.

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Architecture diagram

Figure 1 illustrates the reference architecture for the validated solution.

Figure 1.

Reference architecture diagram for the solution as validated

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Hardware components

Table 2 lists the hardware components used to validate the solution. Table 2.

Hardware components

Item

Units

Description

Storage platform

1

EMC VNX5700 (block), 36 GB system cache

Fabric switch

1

8 Gb/s FC switching module

vSphere host servers

2

4 sockets, 2.66 GHz Intel Xeon X7460 6-core processors, 128 GB RAM

Host bus adapter (HBA)

4

8 GB HBAs (2 per vSphere host)

Replication Manager server

1

4 2.99 GHz Intel Xeon quad-core processors, 32 GB RAM

vCenter server

1

42.99 GHz Intel Xeon quad-core processors, 32 GB RAM

Disks

37

32 for mailbox server content: 5 for virtual machine OS: 2 TB 7.2k rpm NL-SAS

Software

Table 3 lists software components used in solution validation. Table 3.

Software components

Item

Description

VMware ZCS

Version 7.2 Network Edition (64-bit)

VNX5700 Operating Environment

VNX Block software version 05.31.000.5.704 • FAST Cache enabler • SnapView enabler

Multipathing software

EMC PowerPath/VE 5.7

Hypervisor operating system

VMware vSphere 5.0 (5.0.0,623860)

vCenter Server

Version 5.0 (5.0.0,623373) on Windows 2008 Standard Edition R2 (64-bit)

Virtual machine operating system

Red Hat Enterprise Linux Server 5.5 (64-bit)

VSI Plug-in for VMware vCenter

Version 5.2

VSI Unified Storage Management

Version 5.2

Replication Manager Server

Version 5.4.1 on Windows 2008 Standard Edition R2 (64-bit)

Navisphere Admsnap

Version 2.30

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VMware vSphere design As stated in Solution architecture and design, two VMware vSphere servers were configured for VMware HA and VMware DRS to achieve high availability and balanced performance. Each vSphere node in the cluster was configured with sufficient resources to support an entire 10,000-user ZCS environment. In the event of a vSphere cluster node failure, or during vSphere cluster node maintenance, all virtual machines on the affected node were configured to move automatically to the stillfunctioning node. DRS affinity rules

Once all ZCS virtual machines were configured and operational, we distributed them across two vSphere nodes and defined two DRS affinity rules to keep specific sets of Zimbra virtual machines (each virtual machine had a different messaging role) on different nodes. The VMware DRS load-balancing automation level was set to Automatic with a Normal (default) threshold. We defined “Virtual Machines to Hosts” (VM-Host)-type affinity rules. This rule type was introduced in vSphere 4.1 for DRS clusters to augment the existing anti-affinity rules, which are now known as VM-VM rules. VM-Host affinity rules enable you to stipulate that a set of virtual machines either should or must run on specific nodes within a cluster. Unlike a VM-VM rule, which specifies anti-affinity among specific virtual machines, a VM-Host rule specifies an affinity relationship between a set of virtual machines and a set of cluster nodes. A VM-Host rule has either a Required (“must”) attribute or a Preferential (“should”) attribute. Mandatory rules apply to non-DRS operations even in a DRS cluster, such as manual power-on operations, manual vMotion™ operations, and VMware HA host failover events. Because DRS honors VM-Host Preferential (“should”) rules during load balancing operations and node maintenance operations, we chose VM-Host rules (instead of VM-VM rules) to ensure automatic failback of virtual machines to the original node following node maintenance. We defined two VM-Host Preferential rules to stipulate that nodes Host 1 (R900-11) and Host 2 (R900-12) should each host a specific Mailbox Server virtual machine, MTA Server virtual machine, and LDAP Server virtual machine, as presented in Table 4. Table 4.

DRS affinity rules defined for this solution

This rule…

Stipulates that this node…

Should keep…

Keep virtual machines on Host 1 (R900-11)

Host 1 (R900-11)

DRS Group “VMs on (R900-11)”: Mailbox Server 1, MTA Server 1, LDAP Server 1

Keep virtual machines on Host 2 (R900-12)

Host 2 (R900-12)

DRS Group “VMs on (R900-12)”: Mailbox Server 2, MTA Server 2, LDAP Server 2

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Figure 2 shows the DRS VM-Host affinity rules defined for this solution.

Figure 2.

DRS affinity rules defined for this solution

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Storage sizing and configuration Sizing and configuring storage for use with enterprise email systems can be a complicated process, driven by many variables and requirements, which vary from organization to organization. Properly configured storage, combined with optimally sized server and network infrastructures, can guarantee smooth enterprise email operation. Mailbox server building block design methodology

One of the methods that can be used to simplify the sizing and configuration of large amounts of storage on EMC VNX series storage arrays for use with ZCS is to define a unit of measure—a mailbox server building block. A mailbox server building block represents the amount of storage and server resources required to support a specific number of ZCS users. The amount of required resources is derived from a specific user profile type, mailbox size, and disk requirements. Using the building block approach simplifies the design and implementation of ZCS. Once the initial building block is designed, it can be easily reproduced to support the required number of users in your enterprise. By using this approach, EMC customers can now create their own building blocks that are based on their company’s specific email environment requirements. This approach is very helpful when future growth is expected because it makes email environment expansion simple and straightforward. EMC best practices involving the building block approach for storage design have proven to be very successful in many customer implementations.

Building block design

Designing a building block that is appropriate for a specific customer’s environment involves three phases: Collect the relevant requirements, design and build the building block based on the requirements, and validate the design. Phase 1: Collect the requirements In Phase 1, an administrator identifies ZCS user requirements. To gather the necessary information, answer the following questions. Accurate answers to these questions are essential for properly sizing your ZCS servers and storage. •

What is the total number of users in your environment?

• •

What is the user concurrency? What is the mailbox quota per user (MB)?



What is the total number of incoming and outgoing messages per day?

• •

What is the average message size (KB)? What percentage of messages will have attachments?



What is the average attachment size (KB)?



What is the average mailbox utilization percentage of quota?



What percentage of total users will be using Webmail vs. POP vs. IMAP vs. Mobile vs. Outlook?



What is the message delivery peak period in minutes?



Will you be using the Zimbra AS/AV on Zimbra MTAs?

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Zimbra professional services can help with sizing and will use the answers from these questions as input into a Zimbra deployment worksheet. Figure 27 in Appendix B: Zimbra deployment worksheet shows an example of the sizing tab in a Zimbra deployment worksheet. Note: The ZCS deployment worksheet is used only by Zimbra professional services. Phase 2: Design the mailbox server building block Phase 2 involves designing a mailbox server building block that satisfies the requirements collected in Phase 1. The building block includes storage and server resources. Prior to designing your building block, use the following resources to ensure that you have a thorough understanding of the relevant concepts and building block components: •

EMC VNX series storage and VMware vSphere design best practices



ZCS best practices (ZCS wiki)



Recommendations provided by the ZCS deployment worksheet

An example calculation of capacity requirements for ZCS is presented in Appendix A: Example ZCS mailbox server storage space calculation. Phase 3: Deploy the building block and validate its design After the mailbox server building block is deployed, the block’s design can be validated with the Zimbra Soapgen testing tool. Soapgen was developed and is maintained by the Zimbra performance lab. It is a comprehensive and flexible mail server load generator designed to provide functionality similar to Microsoft Exchange Loadgen. Soapgen can test many mail protocols and mailbox profiles. How Soapgen was used to validate the mailbox server building block designed for this solution is explained in the Performance validation and test results section. Note: The Soapgen tool is available only from Zimbra professional services.

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Storage design considerations for Zimbra mailbox servers Storage design directly affects the performance of a ZCS implementation. You must consider current and projected workloads when designing storage for your ZCS deployment. EMC VNX series storage systems can provide the necessary performance for your ZCS mailbox servers. VNX storage offers advanced, performance-oriented enterprise array features such as Fully Automated Storage Tiering (FAST), FAST Cache, thin provisioning, hardware-based snapshots and clones, and many others. ZCS I/O characteristics

Storage must be designed to work optimally with the ZCS application. To do this, ZCS I/O characteristics, I/O patterns, and read/write ratios must be identified. Based on testing performed to validate this solution (test results are presented in the Performance validation and test results section), we identified the types and sizes of I/O generated by ZCS. We observed that ZCS mailbox servers generate primarily small, 4 KB to 32 KB random I/Os to the database. This observation enabled us to size the test environment accurately for optimal performance and the best user experience. ZCS mailbox servers are read/write intensive. Even with appropriately configured RAM on the relevant virtual machines, the message store generates a large amount of disk activity. For the ZCS mailbox server, the majority of I/O activity is generated by these three sources, in decreasing order of load generated: •

Lucene search index managed by the Java mailbox process



MySQL instance that runs on each message store server and stores metadata (folders, tags, flags, and so on)



Blob message store managed by the Java mailbox process

MySQL, the Lucene index, and blob stores generate random I/O and, therefore, should be serviced by a fast disk subsystem. Blob message stores generate less I/O than MySQL or the Lucene index but require more capacity, thus blob stores can be deployed on slower disks in some cases. Note: The target user profile and other customer-specific requirements directly affect storage design recommendations for ZCS. Work closely with EMC and VMware presales support to receive appropriate guidance.

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ZCS mailbox server In a multi-server ZCS deployment, eight major mailbox server partitions are typically planned for use. However, the use of VNX-specific enterprise array features can partitions reduce the number of required partitions. Table 5 provides information about each ZCS mailbox server partition and its function. Table 5.

ZCS mailbox server partitions

Mailbox server partition

Function

/opt/zimbra

Root partition for Zimbra application

/opt/zimbra/db

MySQL database files (holds all metadata)

/opt/zimbra/store

Message store (messages, attachments, etc.)

/opt/zimbra/index

Message index partition for fast user searches

/opt/zimbra/redolog

MySQL database log files

/opt/zimbra/logs

General Zimbra log files

/opt/zimbra/backup

Holds all backup data for the Zimbra mailbox server

/opt/zimbra/store02

Zimbra Hierarchical Storage Management (HSM) Note: It is necessary to deploy a secondary store volume only when the Zimbra Hierarchical Storage Management (HSM) feature is used. HSM allows you to configure storage volumes for older messages. To manage your email storage resources, you can implement a different HSM policy for each message server. Messages and attachments are moved from a primary volume to the current secondary volume based on the age of the message. Archived messages are still accessible by the user.

Mount points

For each LUN created on the VNX storage, we configured a mount point and then created a filesystem on the mounted partition. Each LUN configured for a mailbox server must provide enough performance and capacity based on user requirements and recommendations from the ZCS deployment worksheet. For this solution we configured five LUNs and mounted them to the first five partitions listed in Table 5. Note: If native Zimbra backups (zmbackup) are used, you need a sixth LUN and a mount point (/opt/zimbra/backup). If Zimbra HSM is used, you need to create a seventh LUN and a mount point for the secondary store (/opt/zimbra/store02).

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Message stores

A Zimbra Message Store holds all email messages for a single mailbox server, including the message bodies and any file attachments. Messages are stored in MIME format. The message store is located on each Zimbra server under /opt/zimbra/store. Each mailbox has a dedicated directory named after its internal Zimbra mailbox ID. Mailbox IDs are unique for each server; IDs are not unique system-wide. Zimbra is designed with “Single Copy Storage” (known as “Single Instance Storage” (SIS) in Microsoft Exchange versions prior to Exchange 2010) that allows messages with multiple recipients to be stored only once in the filesystem. On Unix systems, the mailbox directory for each user contains a hard link to the actual file. For this solution, we deployed one primary message store for each mailbox server.

Redo logs

Each Zimbra server generates redo logs that contain every transaction processed by that server. If an unexpected shutdown occurs on the server, the redo logs are used for the following: •

To ensure that no uncommitted transactions remain, the server rereads the redo logs at startup



During restore, to recover data written since the last full backup in the event of a server failure

When the current redo log file size reaches 100 MB, it rolls over to an archive directory. At that point, the server starts a new redo log. All uncommitted transactions from the previous redo log are preserved. In the case of a crash, when the server restarts, the current redo log and the archived logs are read to reapply any uncommitted transactions. When an incremental backup is run, the redo logs are moved from the archive to the backup directory. For this solution, we placed redo logs on 10k rpm SAS disks with RAID1/0 protection.

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ZCS mailbox server Having identified the requirements for storage (I/O, capacity, and bandwidth), servers (CPU, memory), we designed a ZCS mailbox server building block with the building block specifications shown in Table 6. The building block meets the requirements specifications presented in Table 1 for 5,000 heavy users with a 500 MB mailbox size. Each mailbox server ran in a virtual machine. Table 6.

Specifications of the mailbox server building block

Number of users per mailbox server virtual machine

CPUs per virtual machine

Memory per virtual machine

Disk requirements per mailbox server virtual machine based on 500 MB mailbox size and heavy user profile

5,000

4

16 GB

16 disks:

• 10 600 GB 10k SAS in RAID 5 (4+1): Message store

• 2 600 GB 10k SAS in RAID 1/0 (1+1): Index • 2 600 GB 10k SAS in RAID 1/0 (1+1): Database

• 2 600 GB 10k SAS in RAID 1/0 (1+1): Redo logs, Zimbra root

All Zimbra virtual machine VMFS data stores housing the Red Hat Enterprise Linux Server 5.5 operating system were configured from a RAID group made up of five 2 TB 7.2k rpm NL-SAS drives configured with RAID 5 (4+1) protection. Scaling to 10,000 users

To scale the configuration to 10,000 users (two building blocks/mailbox servers), the two SAS disks housing the Zimbra redo logs and Zimbra root partitions can be shared between the two mailbox servers (there is sufficient capacity for this). The second building block, therefore, requires only 16 disks (two fewer than the first building block). This configuration was tested and caused no performance degradation (see the Performance validation and test results section).

Mailbox server disk layout

We configured six LUNs on the VNX array and configured five mount points on each mailbox server. We did not configure a backup volume because we used VNX SnapView snapshots to back up ZCS content. Figure 3 shows the LUN configuration on the VNX5700 storage array for mailbox server storage as viewed with EMC Unisphere:

Figure 3.

LUN configuration for mailbox server storage viewed with Unisphere

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Table 7 shows the devices, mount points, and disks configured for one ZCS mailbox server in this solution. Volume sizes were based on the requirements presented in Table 1 in conjunction with recommendations generated by the Zimbra deployment worksheet. Table 7.

Linux volume configuration and mount points for one mailbox server

Filesystem

Mounted on

LUN Size

/dev/sdb1

/opt/zimbra

40 GB

/dev/sdd1

/opt/zimbra/db

50 GB

/dev/sde1

/opt/zimbra/index

500 GB

/dev/sdc1

/opt/zimbra/redolog

90 GB

/dev/sdf1

/opt/zimbra/store

3.5 TB

Figure 4 shows the same device, mount point, and disk configuration as viewed with a CLI command issued on the mailbox server virtual machine running Red Hat Linux 5.5.

Figure 4.

Mailbox server filesystem details

Table 8 presents the configuration profile of ZCS mailbox server virtual machines deployed on vSphere. Table 8.

Configuration profile of ZCS mailbox server virtual machines

Role

vCPUs

Memory

Disks (VMDKs)

Disk type

vSCSI Controller

ZCS mailbox server

4

16 GB reserved

100 GB: OS (200 GB LUN)

VMFS

0:0 (LSI Logic SAS)

40 GB: Zimbra root/home

RDM/P

0:1 (LSI Logic SAS)

50 GB: MySQL DB

RDM/P

1:0 (LSI Logic SAS)

500 GB: Index

RDM/P

1:2 (LSI Logic SAS)

90 GB: Redo logs

RDM/P

2:0 (LSI Logic SAS)

3.5 TB: Message store

RDM/P

3:0 (LSI Logic SAS)

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Storage provisioning with the VSI plug-in VSI automates and simplifies the task of provisioning storage for VMware virtual machines. VSI is a client-side plug-in and is installed with VMware Infrastructure (VI) Client. Once VSI has been installed and enabled, a new icon is displayed in vSphere client under Solutions and Applications. In the VNX section in vCenter, input the IP address of the SP A/B controllers and your login credentials.

Figure 5.

VSI plug-in for VMware vSphere visible in vCenter under Solutions and Applications

Figure 6.

Enabled EMC VSI visible in Plug-in Manager

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Storage provisioning process with the VSI plug-in

1.

Using VSI, we right-clicked the VMware HA cluster to be configured and selected EMC > Unified Storage > Provision Storage.

Figure 7.

2.

EMC VSI: Provision new storage

We selected the Disk/LUN option so that we could provision storage on the VNX storage array deployed for this solution.

Figure 8.

EMC VSI: Select Disk/LUN

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3.

We then selected one of the storage pools previously configured for this solution in order to create a LUN.

Figure 9.

4.

EMC VSI: Select storage pool

For the data store, we selected the filesystem type VMFS-5.

Figure 10.

EMC VSI: Select filesystem type

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5.

We then selected a volume type of RDM and specified the LUN properties.

Figure 11.

6.

EMC VSI: Specify RDM volume type and LUN properties

Finally, we clicked Finish and VSI created the requested LUN on the VNX array.

Notes •

If you choose VMFS Datastore instead of RDM Volume, the data store name you specify becomes the user-friendly name of the LUN when viewed with Unisphere.



VSI is aware of the EMC FAST VP auto-tiering policy features. These features can be reviewed by clicking the Advanced button.



When provisioning storage with VSI, storage access policies can be set on an individual user basis.

For more information about the VSI plug-in for VMware vCenter, visit the EMC Community Network.

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EMC VSI Storage Viewer plug-in

As shown in Figure 12, the EMC Storage Viewer plug-in provides additional visibility into VNX storage from vCenter. By selecting the EMC VSI tab and selecting a data store or an RDM LUN, you can view details about that volume. To display details about the VNX storage pool in which the LUN resides, select Hard Disk 6 for mailbox server ZMBX04.

Figure 12.

EMC VSI Storage Viewer Plug-in with VMware vCenter

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Configuration guidelines and best practices This section presents the key guidelines and best practices we discovered and applied during the validation of this solution. VNX storage configuration recommendations

Follow these recommendations when configuring VNX storage in the context of this or a similar solution: •

During the configuration of storage pools, RAID groups and LUNs for Zimbra mailbox servers, consider I/O patterns when defining partitions. Separate random workloads from sequential workloads on different disks.



Create dedicated storage pools or RAID groups for ZCS. If your array supports other applications, use different storage pools or RAID groups for those applications.



Size storage not only for capacity but also for performance.



To configure VNX for vSphere clustering, use Unisphere to create a single storage group containing all ESXi host cluster members.

Figure 13.

EMC Unisphere: Storage group configuration for vSphere hosts

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vSphere ESXi host configuration recommendations

Guest virtual machine configuration recommendations

Follow these recommendations when configuring vSphere ESXi hosts for this or a similar solution: •

Install EMC PowerPath/VE to improve performance and maximize host-tostorage I/O throughput



Configure each ESXi host with at least two HBAs connected to different fabrics for best performance and high availability



Make the number of CPU cores equivalent to (or exceed) the number of virtual CPUs you plan to run concurrently (within the set of virtual machines on the ESXi host)



Make physical memory equivalent to the sum of the memory used by the individual virtual machines plus additional memory required for the ESXi host



Plan for host failures within a vSphere cluster so that a single host's resources can sustain the environment with minimum required performance



Install EMC VSI Plug-in, which provides the vSphere administrator with a view of and access to all EMC storage

Follow these recommendations when configuring guest virtual machines for this or a similar solution: •

Install the latest version of VMware tools on guest virtual machines to optimize performance and enhance the user experience



Use multiple SCSI controllers when creating VMDKs for ZCS mailbox server virtual machines. Use separate SCSI bus IDs to spread the I/O load (sequential vs. random) across different SCSI buses.



Reserve memory for each ZCS mailbox server virtual machine



Allocate enough space for a swap file. ESXi Server creates a swap file for each virtual machine that is equal in size to the difference between the virtual machines, configured memory size, and memory reservation. The default is to place the swap file on the same data store as the guest operating system.

Linux filesystem alignment It is necessary to align Linux partitions used for ZCS mailbox servers. The fdisk command can be used to create a single, aligned partition on a second Linux sdb or sdc filesystem LUN to utilize all of the LUN’s available capacity. We used the following procedure to align the Linux filesystem. In this example, the partition is named /dev/nativedevicename: fdisk /dev/nativedevicename # sdb and sdc n # New partition p # Primary 1 # Partition 1 # 1st cylinder=1 # Default for last cylinder # Expert mode b # Starting block 1 # Partition 1 128 # Stripe element = 128 w # Write

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Linux filesystem alignment on very large LUNs To support 5,000 users, each with a 500 MB mailbox, we configured a 3.5 TB message store volume. To create an aligned partition larger than 2 TB, use the GUID Partition Table (GPT) drive partitioning scheme. GPT provides a more flexible mechanism for partitioning drives than the older Master Boot Record (MBR) partitioning scheme. By default, a GPT partition is misaligned by 34 blocks. In Linux, we used the “parted” utility to create and align a GPT partition. The following example shows how to create a partition larger than 2 TB. In this example, the partition is named /dev/sdf. The command aligns a 2.35 TB partition to a 1 MB starting offset. # parted /dev/sdf GNU Parted 1.8.1 Using /dev/sdf (parted) mklabel gpt (parted) p Disk geometry for /dev/sdf: 0.000-2461696.000 megabytes Disk label type: gpt Minor Start End Filesystem Name Flags (parted) mkpart primary 1 2461696 (parted) p Disk geometry for /dev/sdf: 0.000-2461696.000 megabytes Disk label type: gpt Minor Start End Filesystem Name Flags 1 1.000 2461695.983 (parted) q # mkfs.ext3 /dev/sdf1 # Use mkfs to format the file system

Filesystem formatting The following parameters enable filesystem formatting: mke2fs –j –L Label name –O dir_index –m 2 –i 10240 –J size=400 –b 4096 –R stride =16

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Protection (backup and recovery) configuration The native ZCS full backup process can be lengthy, I/O-intensive, and it can degrade performance. To simplify protection processes and keep maintenance windows short, this solution protects ZCS mailbox servers with EMC Replication Manager and EMC VNX SnapView snapshots. The solution uses VNX SnapView snapshot technology to create the Replication Manager replica. VNX SnapView can create or remove a snapshot in seconds, regardless of the LUN size or activity, because it is a point-in-time copy. Compared with the native ZCS backup process, the use of Replication Manager with SnapView significantly reduced the time it took to back up all ZCS mailbox servers. Configuring a VNX SnapView snapshot involves allocating a reserved LUN pool (RLP) with the proper number and size of LUNs (also known as a snapshot cache). For this solution, the reserved LUN pool consisted of 50 20 GB LUNs in one RAID 5 (4+1) group. Note that the actual size of the RLP may be different and depends on the application change rate and recover point objectives (RPO). Preparing ZCS virtual machines for Replication Manager/SnapView snapshots Taking snapshots of ZCS storage requires the following EMC software to be installed on all ZCS virtual machines: •

EMC Replication Manager Agent



EMC Solutions Enabler



EMC Navisphere CLI



EMC Navisphere Admsnap

Once this software is installed, Replication Manager discovers the ZCS virtual machines, as shown in Figure 14.

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Figure 14.

Special consideration for Linux filesystems

EMC Replication Manager: EMC software installed on ZCS mailbox server virtual machine

To reduce snapshot restore time, it might be necessary to adjust either of two Linux filesystem configuration parameters. Linux sets a default value of 30 for the “Maximum Mount Count” parameter. When this value is reached, Linux performs a filesystem check on the disk, which can cause significant mount delay on a large filesystem. For this solution, the message store volume was 3.5 TB. There are two ways to avoid this filesystem check on the mount. The first way is to reset the “Mount Count” value to 1. The second way is to increase the “Maximum mount count” value. For this solution we used the tune2fs utility to change the “Mount Count” value to 1. To set/reset “Mount count” to 1, run this command: tune2fs -C 1 /dev/sdf1

To set “Maximum mount count” to 30 for example, run this command: tune2fs -c 30 /dev/sdf1

Note the difference in the uppercase “C” versus the lowercase “c” in each of the two commands. After the values are reset, you can use the CLI to verify the new values.

Note: Zimbra administrators can monitor snapshot restore time and, if necessary, change these settings as required. Alternatively, a custom script can be created and then run during Replication Manager backup jobs to monitor and adjust settings automatically.

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Backup process with Replication Manager

The Replication Manager Linux File System Agent replicates databases and software applications that store their data in supported Linux filesystems. The filesystem remains mounted for replication. The agent flushes the filesystem I/O buffer immediately before creating a replica to ensure all changes have been synchronized to disk. Pre- and post-replication scripts can be implemented to support other applications and databases, besides those specifically supported by Replication Manager. The scripts can quiesce data to ensure consistency before a split by: •

Shutting down and starting up the application



Putting the database or application into (and out of) an Online Backup mode, if such a mode is available

Note: In order to keep your ZCS environment fully consistent, and to simplify the recovery process, mailbox server backups should be performed together with an LDAP server backup. By doing this, you will avoid out of sync conditions where users’ properties might be changed while their mailboxes are being backed up.

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Figure 15 shows an example of the Replication Manager application set to which we added volumes on the mailbox server housing the Zimbra files. A similar application set should be created for the Zimbra LDAP server filesystem.

Figure 15.

Properties of application set containing ZCS application LUNs

As shown in Figure 16, the Use Consistent Split option was selected to take advantage of VNX consistent-split technology. Pre- and post-replication scripts were implemented to ensure the consistency of ZCS data.

Figure 16.

Use Consistent Split option selected for replication

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Recovery process

The Replication Manager agent automatically unmounts specified Zimbra file systems before it starts a replica restore. It also automatically mounts these Zimbra filesystems after the restore completes. To make the automatic unmount action successful, Zimbra services must be stopped either manually or through an application callout script. Application callout scripts allow you to add customized actions to Replication Manager at several points throughout the replication, mounting, and restore processes. Replication Manager calls these executable scripts based on the names of the scripts and their locations in the Replication Manager host. The callout scripts must be located in the same directory as irccd on the host. The default location in the Linux environment is /opt/emc/rm/client/bin/. The naming convention for callout scripts is as follows: IR_CALLOUT___

is the name of the application set that contains the job that runs the script. is the name of the job that runs the script within the application set. is a number that determines when the script runs, as shown in Table 9. Table 9.

Replication Manager recovery process: Application callout scripts

Callout script number

The script is called…

100

At the beginning of the process

110

At the beginning of failover process (for Celerra iSCSI or VNXe iSCSI replica promotion)

200

Before checking whether target devices are in the correct state

300

Before the application recovery process starts; the 300 callout is valid only for mount operations in which some recovery occurs before filesystems are made visible

400

After checking the application state to verify application recovery is in progress

500

After storage is recovered or mounted

510

After the failover process is complete (for Celerra replica promotion)

550

After the network files have been copied but before the database is recovered; use the 500 callout to make changes to the Oracle initialization file before the application starts

600

After application recovery is complete

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In this solution, the following callout scripts were used: •

IR_CALLOUT_ZMBX01-Zimbra_ZMBX01_Snapshot_100 (to stop Zimbra services)



IR_CALLOUT_ZMBX01-Zimbra_ZMBX01_Snapshot_600 (to start Zimbra services)

Figure 17 shows the Replication Manager GUI used to restore a mailbox server replica.

Figure 17.

Replication Manager: Object selection for restore

Performance results for ZCS backup and restore with Replication Manager and VNX SnapView snapshots, and recommendations for calculating necessary storage space for snapshots, are presented in the Performance validation and test results section.

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Performance validation and test results This section presents the methods used to validate this solution. The test results themselves are presented in subsequent sections. The ZCS test environment deployed in an EMC lab mimicked a typical 10,000-user enterprise email configuration with very heavy user usage profiles and large mailbox sizes. This environment enabled us to observe how ZCS ostensibly performs under extreme enterprise loads. Disclaimer

Benchmark results are highly dependent upon workload, specific application requirements, and system design and implementation. Relative system performance will vary as a result of these and other factors. Therefore, this workload should not be used as a substitute for a specific customer application benchmark when critical capacity planning and/or product evaluation decisions are contemplated. All performance data contained in this report was obtained in a rigorously controlled environment. Results obtained in other operating environments may vary significantly. EMC Corporation does not warrant or represent that a user can or will achieve similar performance expressed in transactions per minute.

Testing methods

To validate this solution, we used the Soapgen load generation testing utility. Soapgen was developed and is maintained by the Zimbra performance lab. It is a comprehensive and flexible mail server load generator designed to provide functionality similar to Microsoft Exchange Loadgen. Soapgen can test many mail protocols and mailbox profiles. Note: The Soapgen tool is available only from Zimbra professional services. Zimbra Soapgen test tool The Zimbra Soapgen utility enables you to test all server functions in a ZCS configuration and has the following features: •

A parser to interpret specific tests in XML



A test task scheduler to schedule tasks for different test accounts; all tasks are submitted to a queue and wait to be picked for execution at the scheduled time



Various test tasks simulate user interaction with Zimbra through the use of different protocols (SOAP, HTML, IMAP, POP3, CalDav, and Blackberry synchronization)

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We used two client virtual machines configured with Soapgen to generate a load of 5,000 heavy enterprise users against each of two mailbox servers (cumulatively, 10,000 users). We used a workload profile that is typical of an enterprise user. This profile is presented in Table 10. Table 10.

Target ZCS user profile characteristics

User profile characteristic

Value

Total users

10,000

Zimbra mailbox servers

2

Users per mailbox server

5,000

User mailbox size

500 MB

User workload message profile

Heavy enterprise

Message profile characteristics

21 received/hour/user, 7 sent/hour/user (224 messages/user/8 hour day) 124 KB average message size 80% with 25 KB message body 20% with 20 KB message body and 500 KB attachment

Test scenarios

User type

90% SOAP users, 10% IMAP users

Concurrency

100%

Read/write ratio based on profile and workload type

40% reads/60% writes

Mail stores per server

1

Blob message store LUN size

3.5 TB per mailbox server

We conducted a series of five tests to validate the performance and scalability of the ZCS mailbox server building block, the benefits of using VNX FAST Cache, the performance of NL-SAS disks with ZCS data, and protection (backup and restore) for ZCS data using Replication Manager with VNX SnapView snapshots. •

Test 1: ZCS mailbox server building block performance



Test 2: ZCS mailbox server building block scalability



Test 3: Advanced protection for ZCS data using Replication Manager with VNX SnapView snapshots



Test 4: Benefits of using VNX FAST Cache with ZCS



Test 5: Performance of NL-SAS disks with ZCS data

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Key performance indicators

For tests 1 through 4, we followed the relevant VMware recommendations on establishing performance targets for a well-performing ZCS environment that provides an optimal user experience. Following each test run, the following key performance indicators were evaluated against target values for each mailbox server. Table 11.

Key performance indicators for tests 1 through 4

Key performance indicator

Target value

ZCS mailbox server CPU utilization

45% to 55% average, 85% maximum

Send mail latency (user experience)

Less than 1,000 ms

Disk latency

Less than 20 ms

Disk utilization

Less than 65%

Disk throughput (KB/s)

Higher number of messages per second is better

Disk IOPS

Higher number of IOPS is better

LMTP delivery rate

Higher number of injected messages per second is better

Tests 1 through 4 examined messages sent/received, moves and deletes, and all other functions performed by an enterprise email user on a regular basis. All tests ran successfully. The Soapgen client performed consistently against the ZCS servers without causing any corruption to any of the ZCS components.

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Test 1 results: ZCS mailbox server building block performance This test involved generating a load equivalent to 5,000 concurrent, heavy users on one mailbox server to evaluate performance and user experience. Another goal for this test was to characterize ZCS I/O types for the purpose of developing storage design guidelines and best practices for deploying ZCS on VNX storage. The VNX array I/O analysis showed that 90 percent of all I/O generated by ZCS was small, 4 KB random I/O. Figure 18 shows a histogram of I/O types generated on the VNX5700 array during two hours of Soapgen peak client load.

Figure 18.

I/O types generated on the VNX5700 array during two hours of Soapgen client load

The results of Test 1 demonstrated that the building block we designed provided solid performance and a significant amount of headroom for additional load. Table 12 presents the performance results for one building block—one ZCS mailbox server virtual machine with a heavy workload of more than 200 messages per user per day. This building block was deployed using 10k SAS disks for all Zimbra volumes. Test results show excellent VNX storage performance with balanced distribution of the user load across ZCS volumes. Very low disk utilization with excellent throughput was also observed during this test. The LMTP delivery rate was approximately 11.84 messages per second injected, 28.41 messages per second received (multiple recipients). This implied heavy MySQL writes.

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Table 12.

ZCS mailbox server building block performance details

Validation parameter

Test results for 5,000 users per server

Zimbra mailbox server CPU utilization

43%

Send mail latency

184.89 ms

LMTP delivery rate

Average received 11.84 messages/sec Average delivered 28.41 messages/sec

ZCS volumes

Disk utilization

Disk throughput

Disk IOPS

Avg. Disk latencies (ms)

Zimbra root volume (/opt/zimbra)

0.21%

923 KB/sec

14

3.78

Zimbra redo logs volume (/opt/zimbra/redolog)

10%

3,890 KB/sec

172

0.41

MySQL DB volume (/opt/zimbra/db)

7%

4,135 KB/sec

129

1.66

Index volume (/opt/zimbra/index)

8%

798 KB/sec

39

3.25

Message store volume (/opt/zimbra/store)

41%

6,507 KB/sec

202

4.58

Total

n/a

16,253 KB/sec

556

n/a

Figure 19 shows throughput and utilization details for each Zimbra volume. VNX storage easily handled ZCS application I/O and produced 16,254 KB/s throughput with 556 IOPS across all disks supporting the 5000-user ZCS mailbox server building block.

Figure 19.

Throughput and utilization details for ZCS volumes in 5,000-user mailbox server building block

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Figure 20 shows the number of disk IOPS for each ZCS volume in the building block, with a total of 556 IOPS across all volumes.

Figure 20.

Number of disk IOPS for each Zimbra volume in 5,000-user mailbox server building block

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Test 2 results: ZCS mailbox server building block scalability For this test, we scaled the environment to two building blocks—to support 10,000 concurrent, heavy users on two mailbox servers—to evaluate performance and user experience. Test results demonstrated excellent performance with only a slight increase in average send mail latency, from 189 ms to 295 ms, which was still significantly below the 1,000 ms maximum target. Table 13.

Performance results for two building blocks (10,000 users): Server utilization and latencies Results for two mailbox servers (10,000 users)

Validation parameter

Mailbox server 1

Mailbox server 2

ZCS mailbox server CPU utilization

45%

43%

Send mail latency

296.06 ms

294.44 ms

LMTP delivery rate

Average received 10.83 messages/sec

Average received 10.26 messages/sec

Average delivered 27.82 messages/sec

Average delivered 25.30 messages/sec

Table 14 presents details of disk throughput and IOPS achieved during the validation of two ZCS mailbox server building blocks. The total throughput of 36,523 KB/s was achieved with 1,445 IOPS across all ZCS volumes and disks. Table 14.

Performance results for two building blocks (10,000 users): Disk throughput and IOPS

ZCS volume

Disk throughput (KB/s)

Disk IOPS

Avg. Disk Latencies (ms)

Zimbra root volume (/opt/zimbra)

1,944

32

4.1

Zimbra redo logs volume (/opt/zimbra/redolog)

8,246

406

0.78

MySQL DB volume (/opt/zimbra/db)

8,878

188

2.1

Index volume (/opt/zimbra/index)

4,030

84

4.2

Message store volume (/opt/zimbra/store)

13,425

255

5.1

Total

36,523

1,445

n/a

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Figure 21 and Figure 22 provide graphical representations of disk throughput, utilization, and IOPS for two 5,000-user mailbox server building blocks (10,000 users).

Figure 21.

Disk throughput and utilization for two building blocks (10,000 users)

Figure 22.

Test Results: Disk IOPS for two building blocks—10,000 users

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Test 3 results: Advanced protection for ZCS data using Replication Manager with VNX SnapView snapshots The goals of this test were as follows: •

Successfully back up and restore critical ZCS data by using Replication Manager with VNX SnapView snapshots



Identify the durations required to back up (replicate) and recover the ZCS data



Determine snapshot space requirements in order to provide sizing guidelines

We successfully created a Replication Manager replica of the critical ZCS data. We then ran Soapgen to simulate a heavy enterprise user workload and evaluated the VNX SnapView snapshot space that was used for the replica. The backup and restore times were very short and the operations were very efficient: •

Replication Time: 2 minutes and 26 seconds



Restore Time: 2 minutes and 9 seconds

Table 15 shows the LUN size and actual data size of each ZCS application LUN that was used in the replication and restore processes. Table 15.

ZCS replication data used for snapshot testing

ZCS application LUN

LUN size

Data size

/opt/zimbra

40 GB

3 GB

/opt/zimbra/db

50 GB

26 GB

/opt/zimbra/index

500 GB

160 GB

/opt/zimbra/store

3.5 TB

2.7 TB

/opt/zimbra/redolog

90 GB

22 GB

Total

4,180 GB

2,911 GB

Snapshot space calculations Figure 23 shows VNX reserve LUN pool usage statistics. During testing we observed that a typical heavy enterprise workload generates around 61 GB of data in the reserve LUN pool. This translates to around 12 MB per user (61 GB/5,000 users). Carefully consider the data change rate and how long the replicas need be kept to determine the size of the reserve LUN pool.

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Figure 23.

VNX SnapView reserved LUN pool usage following Soapgen test

To calculate total snapshot space by using percentage data, we sum all space usage for all LUNs participating in the replication. For this solution, total snapshot space was 61 GB in the SnapView reserved LUN pool. Total snapshot space used = (20 GB * 56%) + (20 GB * 38%) + (40 GB * 50%) + (40 GB * 53%) + (20 GB * 4%) = 11.2 GB + 7.6 GB + 20 GB + 21.2 GB + 0.8 GB = 61GB

Note that 61 GB also includes snapshot metadata that is usually 5% to 10% of the total source LUN space. In the solution as validated, metadata was about 7% (32 GB). Another way to calculate the used snapshot space is to look at the writes to the reserve LUN pool in the SnapView session properties. For this solution, there were around 463,932 writes produced during a two-hour heavy enterprise user load, which consumed 29 GB of space.

Figure 24.

Writes before and after replication, in SnapView session properties

Total snapshot space used = (Writes to RLP after Soapgen test) – (Writes to RLP before Soapgen test) * 64 KB SnapView chunks + (metadata) = (464077 - 145) * 64 KB = 463,932 * 64 KB = 29 GB + metadata

The remaining 32 GB (7%) was used for snapshot metadata. The amount of metadata is a percentage of the total source LUN size (4,180 GB in this case), which is allocated for map entries. Total snapshot space used = 29 GB + 32 GB = 61 GB

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Test 4 results: Benefits of using EMC VNX FAST Cache with ZCS data The goal of this test was to evaluate whether enabling EMC VNX FAST Cache for the storage pool containing the Zimbra store volume (/opt/zimbra/store) would improve the performance and user experience. Because we observed low disk utilization during previous tests with a Sopagen user workload of 200 messages sent/received per user per day, there was no point in enabling FAST Cache with the same workload. We doubled the Soapgen user workload to from 200 messages to 400 messages sent/received per user per day and ran it on one mailbox server for two hours without enabling FAST Cache. We did not change either the CPU or memory configuration on the mailbox server virtual machine. After running this extreme workload (double the heavy user workload) for two hours, we observed that Zimbra mailbox server CPU utilization jumped to 85% and send mail latencies jumped above the 1,000 ms target. This outcome was expected. We then created 200 GB FAST Cache on VNX5700 array (made from two 200 GB SSD drives in RAID 1/0) and enabled it on the LUN configured for the ZCS store volume (/opt/zimbra/store). We then ran the same extreme workload for two hours. After very short warm-up time, FAST Cache began to absorb most of the extra load. Mailbox server average CPU utilization fell to 51% and the average send mail latency fell below the 1,000 ms target. We ran this test several times and confirmed the repeatability of these results. Thus, enabling FAST Cache on the Zimbra store volume permitted the VNX array to handle twice the original workload (400 messages sent/received/user/day) without reducing performance, degrading the user experience, or requiring additional server CPU or memory resources on the ZCS mailbox server virtual machine. At the end of the test only 2% of the 200 GB FAST Cache was used.

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Figure 25 shows the effect of FAST Cache on the Zimbra mailbox server when running an extreme user workload.

Figure 25.

Effect of FAST Cache on Zimbra mailbox server with extreme user workload

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Test 5 results: Performance of NL-SAS disks with ZCS data The purpose of this test was to determine whether the use of 7.2k rpm NL-SAS disks on the VNX5700 array for ZCS data would satisfy the key performance criteria for this solution (see Table 11). As of this paper’s publication, current Zimbra best practices published on the ZCS wiki discourage the use of SATA disks. This guideline, however, is based on older types of SATA without considering the new advantages of using NL-SAS (near-line serial-attached SCSI) disks on EMC VNX5700 storage. NL-SAS drives offer performance and capacity similar to SATA drives, but NL-SAS drives utilize a SAS interface for I/O. For this test, we reconfigured the message store for one of the ZCS mailbox servers and migrated the message store data from a SAS disk pool to an NL-SAS storage pool. The new NL-SAS storage pool had eight 2 TB 7.2k rpm NL-SAS disks in a RAID1/0 (4+4) configuration. This configuration provided 7,323 GB of user capacity and sufficient performance for future expansion. We generated a load equivalent to 5,000 concurrent heavy users on each of two mailbox servers, concurrently, for two hours and monitored the performance. The performance on both severs was almost identical. Both servers successfully met all key performance criteria. NL-SAS disks on VNX5700 storage system demonstrated excellent performance with minimal disk utilization and low latencies. Based on our observations from this test, we can now advise customers to consider using NL-SAS drives for ZCS on EMC VNX series storage provided the user workload profile is similar to the one validated for this solution. Figure 26 shows the results of these tests.

Figure 26.

Performance of NL-SAS disks with ZCS data

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Conclusion The combination of ZCS with EMC VNX series storage provides an optimal collaboration infrastructure. Storage, compute, and network layers maintain high availability, while EMC’s building-block sizing approach achieves predictable performance and a repeatable storage design. Easy scaling with EMC’s buildingblock approach to sizing

EMC’s building-block approach to sizing accelerates your deployment of ZCS. Once deployed, the performance, management, and protection advantages of running ZCS on EMC VNX series storage are self-evident. •

Based on an EMC sizing building block of 5,000 users, your ZCS environment can be scaled in multiples of 5,000 seats. Two building blocks supporting a total of 10,000 heavy users were successfully validated.



The results of testing demonstrated that the building block we designed provided solid performance and a significant amount of headroom for additional load.



Test results showed excellent VNX storage performance with balanced distribution of the user load across ZCS volumes. Results showed very low disk utilization with excellent throughput.



VNX storage easily handled ZCS application I/O and produced 16,254 KB/s throughput with 556 IOPS across all disks supporting the 5000-user ZCS mailbox server building block.

Benefits of EMC VNX series FAST Cache

EMC VNX series FAST Cache accelerates performance to address unanticipated workload spikes.

NL-SAS disk performance with ZCS

NL-SAS disks on VNX5700 storage provide excellent performance with minimal disk utilization and low latencies.

VMware HA clustering



Enabling FAST Cache on the Zimbra store volume permitted the VNX array to handle twice the original workload (400 messages sent/received/user/day) without reducing performance, degrading the user experience, or requiring additional server CPU or memory resources on the ZCS mailbox server virtual machine. By the end of the test run, only 2% of the 200 GB FAST Cache was used.



The performance was almost identical to 10k SAS disks; all key performance criteria were successfully met.



Based on our observations from testing, we can now advise customers to consider using NL-SAS drives for ZCS on EMC VNX series storage, provided the user workload profile is similar to the one validated for this solution.

VMware HA provides uniform high availability across the entire virtualized IT environment without the cost and complexity of failover solutions tied to either operating systems or specific applications.

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EMC Replication Manager and EMC VNX SnapView provide instant snapshot-based Advanced protection (backup backup and recovery for ZCS data. Replication Manager automates the creation of snapshots of ZCS mailbox server volumes using SnapView technology. We and recovery) determined snapshot space requirements in order to provide efficient sizing guidelines. •

Compared with the native ZCS backup process, the use of Replication Manager with SnapView significantly reduced the time it took to back up all ZCS mailbox servers.



The backup and restore times were very short and the operations were very efficient: 

The replication time was 2 minutes and 26 seconds.



The restore time was 2 minutes and 9 seconds.

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References White papers

Product documentation

For additional information, see the white papers listed below. •

Introduction to the EMC VNX Series



Performance Tuning Guidelines for Large Deployments



Zimbra Mail Server Performance on vSphere 5.0

For additional information, see the product documents listed below. •

Zimbra Collaboration Server Datasheet



Zimbra Collaboration Server Documentation



Zimbra Network Edition Multi-Server Installation Guide



EMC SnapView



EMC Replication Manager



VMware vSphere



EMC VSI Plug-in for VMware vCenter (EMC Community Network)

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Appendix A: Example ZCS mailbox server storage space calculation Proper storage sizing is essential for excellent ZCS application performance. You must accurately identify the appropriate types, numbers, and sizes of disks, RAID protection levels, and configuration of the ZCS store volume to satisfy application I/O requirements. The following storage space calculation example is based on a 500 GB mailbox size for each of 5,000 users. (User data) + (MySQL data) + (ZCS binaries) + (ZCS logs) + (ZCS indexes) = Total space



User data: 5,000 users with 500 MB = 2,500 GB user data



MySQL data: 5% of 2,500 GB (user data) = 125 GB



ZCS binaries: 10 GB



ZCS logs: 20 GB



ZCS indexes: 25% of 2,500 GB (user data) = 625 GB

Total space without backups: 2,500 + 125 + 10 + 20 + 625 = 3,280 GB

In this solution we used storage snapshots. The space calculations for snapshots are described in Snapshot space calculations. If ZCS native backups are used, allocate an additional 160% of the space required. •

Backups: 160 % of subtotal: 3,280 * 160% = 5,248 GB

Total space with backups: 3,280 GB + 5,248 GB = 8,528 GB

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Appendix B: Zimbra deployment worksheet Accurate information about your environment is essential for proper sizing of your ZCS servers and storage. Zimbra Professional Services has its own deployment worksheet to assist in sizing your ZCS servers and storage. For some cells, the worksheet supplies values recommended by VMware based on related input. Figure 27 shows an example of the sizing tab in a Zimbra deployment worksheet. Note: The deployment worksheet is used only by Zimbra Professional Services.

Figure 27.

Example of sizing tab in a ZCS deployment worksheet

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