Breaking the Artificial Database Size Limit in Exchange 2007 Standard Edition

Thursday, March 26, 2009

Exchange Server 2007 has a theoretically unlimited database storage capacity. In reality the limit is 16TB, and this limit is the same in both Standard and Enterprise editions. The storage differences between these two editions have to do with the maximum number of storage groups and databases that can be placed on each server.


Exchange 2007 Standard Edition:
Storage Group – up to 5, Database per SG – up to 5, Database limit – 16 TB.

Exchange 2007 Enterprise Edition:
Storage Group – up to 50, Database per SG – up to 50, Database limit – 16 TB.


Even though E2K7 Standard has a hard 16TB database size limit, there is an artificial limit imposed in the registry. The default cap in RTM is 50GB and the default cap in SP1 is 150GB. Here's how to change this artificial limit:

  • Open RegEdit and navigate to:

HKLM \ SYSTEM \ CurrentControlset \ Services \ MSexchangeIS \ servername \ Private-{respective-DB-GUID}

  • Create a new DWORD value "Database Size Limit in Gb"


  • Assign its decimal value (in GB). For example, enter decimal 200 for a 200GB artificial limit.


  • Restart the Microsoft Exchange Information Store service

Note: E2K7 Enterprise Edition does not have an artificial limit.

Note: If the Exchange Server Best Practices Analyzer (ExBPA) finds that the Database Size Limit in Gb value is present and configured, the Exchange Server Analyzer displays a non-default configuration message.