Exchange 2000 WebStore Strategies
First, let me say that you should embrace Exchange 2000 applications <grin>. Translation: if you provide a basic service level agreement and think of yourself as an application hosting service, you will be able to provide a better system and infrastructure for Exchange 2000 applications.
Wise Exchange professionals have always encouraged companies to devote computers to Exchange applications. Sure, you can run an Exchange application and mailboxes on the same server, but what happens when the Event Service hangs (that never really happens anyway <grin again>), or you need to stop the Exchange services in order to install a new custom agent you created. The point is: you need to be able to take an application server offline and not affect someone's ability to check their mail. Also, many larger shops do not run the Public store on all servers.
Exchange 2000 applications are much more reliable than those running on Exchange 5.5. For one thing, there is no single Event service that processes scripts. Not only that, we no longer have to break the rules in order to get our collaborative applications to work (Anybody use the Exchange 5.5. routing objects?). Because of this new added stability, a great many companies are now looking to centralize the Exchange 2000 application servers within their company. It makes sense really; the application data does not always need to be pushed out to the fringes like a mailbox. Also, centralization allows you to formally support the equipment and data in the folder trees.
Figure 1: Data Center Distribution Scenario
In the scenario shown in Figure 1, we could place a single dedicated application server in each data center. This server could take advantage of the Storage Area Network (SANs), Uninterrupted Power Supply (UPS) and spare equipment already available in the data centers as well as localized Redundant and Independent Disks arrays. (RAID). The Service Level Agreement (SLA) and replication requirements dictate where the application actually resides, but we can’t decide on that yet. Our main goal is to provide a base-level application server near each large user population.
Many companies are comfortable with Windows/Exchange 2000 Active/Active server clustering. This and other technologies could be tested in order to move to the next step of redundancy and growth. Such a natural progression would entail adding a second server to each location and configuring the new application server to serve as an active cluster with the first server. So what really determines the number of servers or databases you need?
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