How to set the Exchange 2010 Database Size

Lots of people have been asking what the default size limits for Exchange 2010 databases are so I thought I would drill into that a little for you.

In Microsoft Exchange Server 2010 Standard Edition, there is a default “soft” database size limit of 50 GB. This can be increased as is required.

In Microsoft Exchange Server 2010 Enterprise Edition, there is no default limit configured.

To adjust the soft limit in Standard Edition, you’ll need to make a registry change and then restart the information store. The registry change is outlined in this article:

PLEASE Note that the change is case sensitive.

If you do copy directly from the TechNet article, please watch out for a trailing whitespace as this can cause you some unlooked for pain…

Once you have the registry key set correctly and have restarted your information store, you will see the following event log entry: -

Log Name: Application
Source: MSExchangeIS Mailbox Store
Date: 25/10/2010 16:07:52
Event ID: 1216
Task Category: Storage Limits
Level: Information
Keywords: Classic
User: N/A
Computer: srv.domain.local
Description: The Exchange store Mailbox DB1 is limited to 75 GB. The current physical size of this database (the .edb file) is <1 GB. If the physical size of this database minus its logical free space exceeds the limit of 75 GB, the database will be dismounted on a regular basis.

As with Exchange databases since 2003 SP2, when the limit is reached, the database will be dismounted. It can be remounted again immediately but will be dismounted again as soon as the limit is checked.

Whitespace in the Exchange database is still taken into account when the size is calculated and is referred to as “logical free space” in the event log.