One of the enhancements provided in Exchange Server 2003 service pack 2 (SP2) is the increase of the maximum database size for Exchange Server 2003 standard edition from 16GB to 75GB. I originally thought that it was just a case of installing the service pack after which the database would be allowed to grow past the 16GB barrier but as Microsoft knowledge base article 912375 and the database size limit configuration and management article in the Microsoft Exchange Server TechCenter describe, the limit actually needs to be configured manually.

Scott Lowe’s article at TechRepublic details the necessary configuration as follows:

1. Start the registry editor and browse to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MSExchangeIS\servername\storeguid.
2. Create a new DWORD value named Database Size Limit in GB and set it to a size between 1 and 75.
3. Restart the Microsoft Exchange Information Store service.

This configuration method can be used with Exchange Server 2003 standard edition to configure (on a per-store basis) any value between 1GB and 75GB and for enterprise edition (which has no limit by default) to enforce a limit of up to 8000GB if required; however if the Exchange server is recovered using the /disasterrecovery switch, the registry keys will need to be recreated.