Storage Design Goals in Exchange 2000 Server

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In designing the storage architecture of Exchange 2000 Server, the creators had three goals in mind. The first was to minimize loss of productivity when a database goes off line. Exchange 2000 Server achieves this goal by spreading users across multiple databases that can each be mounted (started) or unmounted (stopped) individually. If one database in a storage group goes off line for some reason, the other databases continue to run, minimizing the number of users who are affected by the downtime.

A second design goal was to allow a single server to host more users than is pragmatically possible in Exchange 5.5. Spreading the users across multiple databases on a single server accomplishes this goal as well. Since the databases are smaller, creating more databases on each server allows each server to host more users. For instance, it is easier to manage six databases with 1000 users per database than it is to manage one database of 6000 users. Not only can backup and restore times be scheduled individually and run faster, but if one database becomes corrupted, only 1000 users are affected instead of 6000 users. In addition, Exchange 2000 Server can group multiple databases into a single storage group and host multiple storage groups on a single server.

The third goal, better recoverability in the event of a disaster, was a major concern of the design team and is also achieved by spreading users across databases, allowing individual databases to be restored while other databases are running. The result is shorter downtimes and greater productivity for users because only a subset of the organization's users are affected when a database goes off line.