Optimizing Storage for Exchange Server 2003
Are you planning to deploy Microsoft® Exchange Server 2003? Are you concerned about availability, fault tolerance and performance? If so, it is critical that you understand how to optimize your storage system for Exchange Server 2003, regardless of the size of your organization.
Disk subsystem bottlenecks cause more performance problems than server-side CPU or RAM deficiencies, and a poorly designed disk subsystem can leave your organization vulnerable to hardware malfunctions. Specifically, your disk subsystem is performing poorly if it is experiencing:
Average read and write latencies over 20 ms.
Latency spikes over 50 ms that last for more than a few seconds.
High disk latency is synonymous with slow performance. To reduce costly disk latency issues, at a minimum, you should:
Invest in high performance disks and spindles It is better to have smaller capacity disks that utilize each spindle's performance than to use fewer spindles with large capacity. Fast storage with a sufficient amount of spindles is one of the most important investments you can make in your messaging infrastructure.
Consider performance before capacity Relying on capacity as the primary metric for storage sizing often results in poor performance for your disk subsystem. For example, most administrators who select a RAID-5 solution do so to maximize storage usage. However, in many cases, properly sizing the performance of your spindles requires you to use more physical disks for RAID-5 than RAID-1+0.
Align your disks Use Diskpart to verify that your disk tracks are sector-aligned. By using Diskpart to create aligned partitions (as compared with non-aligned partitions that are created with Disk Manager), you can increase disk performance by 20 percent. For detailed steps, see How to Align Exchange I/O with Storage Track Boundaries. Note that Diskpart can only be used with basic disks. Diskpart cannot be used with dynamic disks. Diskpart is part of the Windows Server 2003 Service Pack 1 Support Tools. Diskpart supersedes the functionality found in Diskpar, a Windows 2000 Server Resource Kit tool.
All of these topics are discussed in detail later in this guide. In general, to optimize your storage system and avoid high disk latency issues, you need to understand:
The causes of Exchange disk I/O.
How to calculate your disk I/O requirements.
How to optimize your specific storage architecture.
How to verify the performance of your storage system.
Note
Download Optimizing Storage for Microsoft Exchange Server 2003 to print or read offline.
Who Should Read This Guide?
This guide is intended to benefit information technology (IT) professionals who are responsible for planning and designing Exchange messaging systems. The following table lists the specific roles and responsibilities of these professionals:
Audience roles and responsibilities
| Role | Responsibilities |
|---|---|
Storage architects |
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System architects |
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System administrators |
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Messaging administrators |
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Before You Begin
This guide includes advanced storage information that can only be successfully applied if you have a working knowledge of disk subsystem components. Therefore, if you do not have that knowledge, you should first familiarize yourself with Windows storage concepts. For information about Windows storage concepts, see Disk Subsystem Performance Analysis for Windows.
That paper includes references to basic Exchange architectural elements such as stores, storage groups, and transaction logs. If you are not already familiar with these elements and how they are implemented in Exchange, see "Managing Mailbox Stores and Public Folder Stores" in the Exchange Serve 2003 Administration Guide.