Exchange mailbox size limits

Scott mailed me with some questions about the Exchange stores, the differences between standard and Enterprise edition and how to upgrade from standard to enterprise edition.

Well with standard edition you are:

  • Limited to 1 mailbox store database per server
  • Limited to 1 MAPI public store database per server

The limit for database size in standard edition is 16GB.  This means you can only create a single public or private store, each of which can only grow to 16GB in size.  Have a look at this section in the deployment guide for more information.  You can have additional public folder stores however, each are associated with a general purpose folder tree (read the KB article for an explanation of the tree types). Each store has it’s own set of database files (.edb, .stm) and transaction logs.  There’s a good explanation about how public folders work on the Exchange team blog too…

If you’re struggling because your standard edition database has reached the 16GB limit, there is a temporary workaround (a registry key entry Temporary DB Size Limit Extension ) that you can use to increase the size of the DB to 17GB, clean up files, and upgrade to Enterprise edition.

Oh, and to upgrade from Standard edition to Enterprise edition?  Put the CD in and select the reinstall option!…