Exchange on ProLiant Servers

Exchange has been a popular application on ProLiant servers. HP has a whole section on its Active Answers Web site regarding sizing and configuration, benchmarks, planning tools, and information on storage solutions. This can easily be found at http://h71019.www7.hp.com/ActiveAnswers/Render/1,1027,2366-6-100-225-1,00.htm or by going to http://www.hp.com/solutions/activeanswers, and then selecting the Messaging & Collaboration link, followed by the Microsoft Exchange Server link.

GC Servers

Exchange 2003 uses the AD extensively. This DS functionality is provided by Windows 2003 GC servers. GCs provide a partial attribute list of all objects from all domains within the forest. This means that the GC holds information that is relevant to Exchange 2003 such as the

• GAL

• Routing topology

• Administration model

In tuning the network, GC placement is critical. A GC server should be placed "near" Exchange 2003 servers on the network (same network segment).

Based on best practices and Microsoft's recommendation, one GC server processor should exist for every four Exchange processors (all processors being equal speed). Although this recommendation doesn't include the number of users per server figure, you'll find that it's the number of Exchange servers that matter rather than the number of users that it hosts . This recommendation is for GC requirements for use by Exchange 2003 servers only. Again, these are just "rules of thumb," and your environment might define a rule specific to your situation. As an example, the HP internal deployment and best practices for GC configuration is one GC server for every 3,500 mailboxes hosted in a datacenter.

The configuration for these GCs is shown in Table 12.7.

Table 12.7. GC Hardware Configuration

Count	Part #	Description
1	257917-001	ProLiant DL380 G3 P2400-512K 512MB
1	257913-B21	Xeon 2400/512 processor
2	300680-B21	2GB PC2100 DDR ECC SDRAM Memory Option Kit (2x1GB)
4	286775-B22	18.2GB Wide Pluggable U320 15K Drive (1'')
2	286776-B22	36GB 15K U320 UNI HDD ALL
1	227251-001	Remote Insight Board Lights-Out Edition II
1	313054-B21	Compaq Hot Plug Redundant Power Supply Module DL380 G3
1	293048-B21	Hot Plug Redundant Fan Kit for DL380 G3
1	255514-B21	Smart Array 5i Plus Controller & BBWC Enabler for DL380 G3

Based on the earlier criteria, in the example environment, the following guidelines for GC placement for Exchange will be followed:

• Every site that hosts an Exchange server must have at least one GC server.

• Any datacenter hosting Exchange servers will have, at a minimum, two GCs to serve Exchange. This will ensure a GC is available should one fail.

• If multiple exchange servers exist, then the deployed number of GC servers should be equal to one GC processor for four Exchange processors. If this equates to a single GC, then an additional GC must be placed for redundancy.

It is possible that in your environment, there will be Windows 2003 sites that do not have any Exchange servers, but host local GC services for its Windows/Outlook clients. The Outlook clients in this instance will not, by default, use the GC servers in their Windows 2003 site, but instead will use one of the GCs referred to it by the Exchange server. These GCs will typically reside in the same site as the Exchange servers. Over low-bandwidth links, this situation can generate excessive network traffic when Outlook tries to contact the GC server. To avoid this, Registry settings (that vary by client version) can be set on the client to direct the Outlook clients to use the local GC server from its own site. There are limitations to setting these Registry keys, and you need to be fully aware of their impact before broadly setting them for all clients. Testing, again, is essential before rolling out such a change.