Microsoft® Exchange Server 2003 Scalability with SP1 and SP2

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5

Optimizing Exchange 2003

5.1 Introduction to Exchange 2003 Optimization

As you deploy Exchange 2003 in an enterprise, you have to make consider-

ations for the consolidation opportunities and the necessity to place servers

in close proximity to the end users. With the introduction of cached mode

in Outlook 2003, the ability to centralize Microsoft Exchange servers has

been significantly increased, and we now see deployments for large multina-

tional companies that are confined to one or two data centers.

In the case where cached mode is not appropriate, online mode through

either Outlook or by the means of Outlook Web Access will require rela-

tively good network connectivity, providing both sufficient bandwidth and

relatively low latency.

In either of these two deployment approaches, you must work on how

to best optimize server resource utilization and the Microsoft Exchange

software configuration, in addition to server components such as CPU,

memory, and I/O (both storage and network related). The optimization

strategy, however, varies depending upon the type of deployment—whether

you adopt a scale-up solution that aims at gathering as high of a workload

on as small number of servers or decide to distribute the workload on a

number of servers. This latter approach is referred to as scale-out and calls

for the ability of the software components of Microsoft Exchange to prop-

erly distribute their operations.

Each approach is valid and may be mixed, depending upon the server

role. For instance, mailbox servers tend to scale up and host many users per

Windows server, while bridgehead servers can be easily scaled out, utilizing

less powerful machines (two processors, 2-GB RAM) but in several

instances, for helping on availability and easily scaling up if demand rises.

330 5.1 Introduction to Exchange 2003 Optimization

Each of these deployments requires a different type of hardware and

software configuration, which is discussed in this chapter.

Some of the optimizations must be done regardless of the client type,

server role, and topology but more inline with the actual server hardware

configuration.

For example, the use of clustering and the need for fast and reliable

failover requires necessary certain modifications in the Exchange 2003

STORE configuration that are not present by default.

Optimization and tuning in Microsoft Exchange is typically done either

by means of a Windows Active Directory parameter change in the configura-

tion naming context and Exchange service container or using the server reg-

istry. There is a clear advantage in using Windows Active Directory–based

configuration settings, as they can be done centrally, replicated throughout

the enterprise network, and picked up by the server next time the Microsoft

Exchange services are restarted. Some of these settings include most of the

optimization required for storage groups and database engines.

The optimization technique will not only depend upon the server role,

as we explained earlier, but also upon the mode of utilization of Microsoft

Exchange. If you use X.400 transport for connecting into legacy Exchange

5.5 servers or foreign mail systems, you will require some setting optimiza-

tion, which would not apply if you were to use native SMTP communica-

tion across the network.

Although this distinction was quite necessary as Exchange 2000 was

introduced, you will find that most deployments are now using the default

SMTP transport, and we should be focusing on this transport for optimiza-

tion: in that case, the communication layer between the Internet informa-

tion service process and the STORE process should be as optimized as

possible, as well as any data processing that might be required, such as con-

tent conversion, SPAM fighting, and virus detection/prevention.

Finally, some deployments require very specific optimization, such as in

service providers’ environments, in which a large concentration of users is

gathered, with small activity during most of the day, except for peak access

hours. The utilization of POP or IMAP clients can be improved with

Exchange 2003, saving precious CPU cycles used for handling connections

during peak periods. Another example is the optimization of the Windows

Active Directory topology such that minimal replication latency is found

between the servers used for provisioning and the Microsoft Exchange serv-

ers themselves. Backup and recovery tend to be fairly critical in these envi-

ronments, although we must accept the fact that messaging is now