Modify Exchange database size limit & event id: 9688

Event ID: 9688
Source: MSExchangeIS Mailbox Store

Exchange store ‘<storage group name>\<database name>’: The logical size of this database (the logical size equals the physical size of the .edb file minus the logical free space) is 94 GB. This database size is approaching the size limit of 100 GB. If the logical database size exceeds the maximum size limit, it will be dismounted on a regular basis.

To change the size limit of the Exchange 2007 database do the following on the mailbox server:
1. In Exchange Management Shell run this command to get the database GUID:
Get-MailboxDatabase -Identity “<server name>\<storage group name>\<database name>” | Format-Table Name, GUID

2. Start regedit and locate the following key:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MSExchangeIS\<SERVER NAME>\Private-<database GUID>

3. If the DWORD key “Database Size Limit in Gb” exists, change the value to desired size in GB.4. If the DWORD key “Database Size Limit in Gb” does not exists, create a new DWORD key with the name Database Size Limit in Gb and change the value to desired size in GB.

4. Restart the Exchange Information Store service.

For more information:
http://technet.microsoft.com/en-us/library/bb232092.aspx
http://technet.microsoft.com/en-us/library/aa998066%28EXCHG.65%29.aspx