The Exchange Database

The Exchange database consists of the following files:

• MAPI: The Messaging Application Programming Interface is used by Outlook and other mail clients to read and put information into the Exchange database.

• .EDB file: Contains data placed in the Exchange database.

• .STM file: The streaming database file contains common Internet formatted content, such as Multipurpose Internet Mail Extensions (MIME) content.

  • The file is only present within Exchange 2000 & 2003. Exchange 5.5, 2007 and 2010 does not contain .STM files.

• .LOG files: Exchange Server database transaction logs record all changes to an Exchange Server database.

  • Transaction logs for Exchange Server 5.5, 2000, and 2003 are 5 MB in size.

  • Transaction logs for Exchange Server 2007 and Exchange Server 2010 are 1 MB in size.

• .CHK files: Checkpoint files used for recovering (playing) data from transaction logs into EDB files. The checkpoint is the place marker file that indicates which transactions have been committed.

• .PAT files: Used to record information on page splits in Exchange 5.5 through Exchange 2000 (SP1). In Exchange 2000 (SP2) and later, the functionality provided by PAT files is incorporated into Exchange log files.