Configuring Exchange Server 2003 for Maximum Performance and Reliability

After decisions have been made about Active Directory design, Exchange Server placement, and client access, optimization of the Exchange Server itself helps ensure efficiency, reliability, and security for the messaging platform.

Designing an Optimal Operating System Configuration for Exchange

As previously mentioned, Exchange Server 2003 operates best when run on Windows Server 2003. The enhancements to the operating system, especially in regard to security, make Windows Server 2003 the optimal choice for Exchange. Unless clustering or network load balancing is required, which is rare for smaller organizations, the Standard version of Windows Server 2003 can be installed as the OS.

NOTE

Contrary to popular misconception , the Enterprise version of Exchange can be installed on the Standard version of the Operating System, and vice versa.

Although there has been a lot of confusion on this concept, both versions of Exchange were designed to interoperate with either version of Windows.

Avoiding Virtual Memory Fragmentation Issues

Windows Server's previous iterations have suffered from a problem with virtual memory (VM) fragmentation. The problem would manifest itself on systems with greater than 1GB of RAM, which run memory- intensive applications such as SQL Server or Exchange. The Advanced Server Edition of Windows 2000 enabled a workaround for this problem, in the form of a memory allocation switch that allocated additional memory for the user kernel.

Windows Server 2003 includes the capability of using this memory optimization technique in both the Standard and the Enterprise versions of the software, so that the switch can now be used on any Windows Server 2003 system with more than 1GB of physical RAM. The switch is added to the end of the boot.ini file, as illustrated in Figure 4.5.

Figure 4.5. boot.ini parameter switch setting.

The /3GB switch tells Windows to allocate 3GB of memory for the user kernel, and the /USERVA:3030 switch optimizes the memory configuration, based on tests performed by Microsoft that determined the perfect number of megabytes to allocate for optimal performance and the least likely instance of VM fragmentation.

Configuring Disk Options for Performance

The single most important design element, which improves the efficiency and speed of Exchange, is the separation of the Exchange database and the Exchange logs onto a separate hard drive volume. Because of the inherent differences in the type of hard drive operations performed (logs perform primarily write operations, databases primarily read), separating these elements onto separate volumes dramatically increases server performance. Keep these components separate in even the smallest Exchange server implementations . Figure 4.6 illustrates some examples of how the database and log volumes can be configured.On Server1, the OS and logs are located on the same mirrored C:\ volume and the database is located on a separate RAID5 drive set. With Server2, the configuration is taken up a notch , with the OS only on C:\, the logs on D:\, and the database on the RAID5 E:\ volume. Finally, Server3 is configured in the optimal configuration, with separate volumes for each database and set of logs. The more advanced a configuration, the more detailed and complex the drive configuration can get. However, the most important factor that must be remembered is to separate the Exchange database from the logs wherever possible.

Figure 4.6. Database and log volume configuration.

Working with Multiple Exchange Databases and Storage Groups

The Enterprise version of Exchange Server 2003 not only enables databases of larger than 16GB, it also enables the creation of multiple separate databases on a single server. This concept gives great flexibility in design while enabling reduced downtime and increased performance.

A storage group is a logical grouping of databases that share a single set of logs. Each Exchange Server 2003 Enterprise system can handle a maximum of 4 storage groups per server, and each storage group can contain a maximum of 5 databases. This means that each server could theoretically hold up to 20 databases.

In practice, however, each instance of a storage group that is created uses a significant amount of resources, so it is wise to create additional storage groups only if absolutely necessary. Multiple databases, on the other hand, can solve several problems:

• Reduce Database Restore Time Smaller databases take less time to restore from tape. This concept can be helpful if there is a group of users who require quicker recovery time (such as management). All mailboxes for this group could then be placed in a separate database to provide quicker recovery time in the event of a server or database failure.

• Provide for Separate Mailbox Limit Policies Each database can be configured with different mailbox storage limits. For example, the standard user database could have a 200MB limit on mailboxes, and the management database could have a 500MB limit.

• Mitigate Risk by Distributing User Load By distributing user load across multiple databases, the risk of losing all user mail connectivity is reduced. For example, if a single database failed that contained all users, no one would be able to mail. If those users were divided across three databases, however, only one-third of those users would be unable to mail in the event of a database failure.

• Provide for a Recovery Storage Group Exchange Server 2003 provides a concept called a recovery storage group, which enables the creation of a special storage group to which entire databases can be restored. This can be run on a production mail server and can greatly simplify the task of restoring mailbox data to production accounts.

NOTE

One disadvantage to multiple databases is that the concept of single-instance storage is lost across databases. Single-instance storage occurs when only one copy of an email message sent to multiple people is stored on the server, dramatically reducing the space needed to store mass mailings. Each separate database must keep a copy of mass mailings , however, which increases the aggregate total size of the databases.

Clustering for Exchange Server 2003

Exchange Server 2003 is configured to use Windows Server 2003 clustering for enhanced redundancy and increased uptime. Clustering can be set up with up to 8 cluster nodes with the Enterprise version of Windows Server 2003. Clustering is an expensive option, but one that will increase reliability of the Exchange Server 2003 implementation.

NOTE

Microsoft no longer recommends a full active-active clustering configuration. Consequently, at least 1 cluster node should be configured as passive. With 8-way clustering, this means that 7 nodes can be active, and 1 node passive.

Monitoring Design Concepts with Microsoft Operations Manager

The enhancements to Exchange Server 2003 do not stop with the improvements to the product itself. New functionality has been added to the Exchange Management Pack for Microsoft Operations Manager (MOM) that enables MOM to monitor Exchange servers for critical events and performance data. The MOM Management Pack is preconfigured to monitor for Exchange-specific information, and enable administrators to proactively monitor Exchange servers.

Backup and Restore Design Concepts and the Volume Shadow Copy Service

The backup and restore functionality for Exchange Server 2003 has been enhanced via integration with the Volume Shadow Copy Service (VSS) of Windows Server 2003. VSS enables an Exchange database to be backed up via snapshots of the database, which create full data images that can be used for restores . This functionality can also be leveraged by software companies that create backup software for Exchange to further improve the capabilities for Exchange Server 2003 backup and restore.

Uncovering Enhanced Antivirus and SPAM Features

Exchange Server 2003 provides an improved Anti-Virus API (AVAPI), which enables preemptive identification of potential viruses in email attachments. The improved AVAPI can be integrated with antivirus software for Exchange written by third-party software companies and helps secure an Exchange environment.