XADM: Information Store Shuts Down; Database at Maximum Size

The Microsoft Exchange information store service shuts down. In the Windows NT application event log, the following event is logged:

The Microsoft Exchange information store utilizes the Exchange database engine. The maximum allowed size of a single database in Exchange versions 4.0 and 5.0 is 16 GB (Priv.edb can be 16 GB and Pub.edb can be 16 GB). After the limit is reached, the Exchange database engine stops taking transactions and notifies the information store to shut down.

NOTE: Microsoft Exchange Server 5.5 Enterprise Edition information store databases are not limited to 16 GB; they are limited only by available hardware.

The database (Priv.edb or Pub.edb) that has hit the 16-GB limit must be decreased so that the affected process can be started and remain started.

First, the affected database must be defragmented to reclaim any free space. This can be accomplished by doing the following:

1. Defragment the database. To do so, run the following command:
   edbutil /d /ispriv
   -OR-
   edbutil /d /ispub
   NOTE: If you are using the 5.5 version of Microsoft Exchange Server, run the following command:
   eseutil /d /ispriv
   -OR-
   eseutil /d /ispub
2. Start the information store service, let it run for a couple of minutes, and then stop the service gracefully. (This is done to make sure all uncommitted transactions are flushed into the database; see the "More Information" section later in this article for details.)
3. After the process is back up and running, perform a FULL online backup.
   -OR-
   After the process is back up and running, stop the information store service and perform an offline backup of the Exchsrvr\Mdbdata directory.

Defragmenting the database should result in a decrease in size of the database; however, it is possible that the database will still be very close to the 16-GB limit. Therefore, steps must be taken to decrease the amount of information in that database. This can be accomplished by either moving some users from this server to another server with more free space, or implementing personal information store (PSTs) for users and having them move mail into PSTs. The Mailbox Resources tab in the Microsoft Exchange Administrator program can assist the system administrator in finding the largest mailboxes.

It is a good idea to implement storage limits on user mailboxes in the private information store. Storage limits can be configured through the Exchange Administrator program and will help prevent from the database reaching the 16-GB limit.

For more information about use of personal folders and storage limits, see the online documentation.

NOTE: If users are moved to another server, the information store should be defragmented again by running edbutil /d /ispriv or edbutil /d /ispub so as to reclaim the space used by the users who were moved.

When the Exchange database is committing a transaction from a log file and that transaction, if committed, will make the database surpass the 16-GB limit, the Exchange database engine takes the following steps:

1. The transaction is wholly rolled back, meaning that no part of the transaction succeeds, and the checkpoint holds a pointer to this transaction in the log file where it was contained.
2. The Exchange database engine alerts the information store that the 16-GB limit has been reached.
3. The information store then performs a graceful shutdown of the service.

After the database size has been decreased and the service is restarted, the transactions that were not committed because the limit was reached will be committed. To ensure this happens, do this: After the information store is restarted following the defragmentation, stop the service again. This causes all the log files to be committed into the database.

If you are using Exchange Server 5.5 Standard Edition and plan to upgrade to Exchange Server 5.5 Enterprise Edition with unlimited storage, you do not need to defragment the database. Run Setup.exe from the Exchange Server 5.5 Enterprise CD-ROM or Srvmax.exe from the Select CD-ROM.