Changing Store Limits in Exchange 2003 SP2

Changing Store Limits in Exchange 2003 SP2

By default, the size limit of each database on a server running Exchange 2000 and Exchange Server 2003 Standard Edition is 16 GB (this limit is also enforced in SBS 2000/2003). Exchange Server 2003 Service Pack 2 (SP2) is supposed to remove this limit and thus allow for further DB size growth – Changing Store Limits in Exchange 2003 SP2.

After installing Exchange Server 2003 Service Pack 2, the default size limit for each Exchange database is 18 GB, but can easily be configured to allow for database size limits of up to 75 GB per database (for the Standard and SBS 2003 versions), or up to 8000 GB (or 8 TB) per database (for the Enterprise version).

By default, Exchange 2003 SP2 logs events when the database has grown to within 10% of the configured database size limit (i.e. using 90% of the allocated limit). This threshold is configurable and can range from 1% to 100%.

The database size check happens at 5am, every 24 hours by default. This time can be changed through the registry. The first database size check will not take the database offline if the size limit has been exceeded, but an error event (ID 9689) will be logged in the Application event log (i.e. it has reached the 18 GB limit, or any other limit you have manually set).

On the second check (24 hours later) the error event will be logged in the Application event log and the database will be taken offline. An administrator can then mount the database but he or she will have 24 hours fix this issue before the database goes offline again.

Important note: Exchange 2003 SP2 now calculates the logical size of the store, and not the actual size it takes on the hard disk. For example, if you have a 30 GB store (.EDB + .STM files combined) but within it you have 5 GB of white space (look at event id 1221) then Exchange will look only at 25 GB – the logical size.

Note: Exchange 2000 Standard Edition and SBS 2000 do not have this feature and continue to have the 16 GB limit enforced.

To configure the database size limit for a database:

1. On the computer running Exchange Server, start Regedit.exe.
2. Open one of the following registry keys:

• To configure the database size limit on a mailbox store, use the following registry key:

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\MSExchangeIS\Server name\Private-Mailbox Store GUID

• To configure the database size limit on a public store, use the following registry key:

  HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\MSExchangeIS\Server name\Public-Public Store GUID

Note: In some cases you might find more than one “Private-Mailbox Store GUID” and “Public-Public Store GUID” values in the above registry path. These values can be determined by looking at the objectGUID attribute of each store.

In order to view this value you should use a tool like LDP.exe or ADSIEDIT.msc (both can be found in the Windows Server 2003 Reskit Tools).