Backing up Exchange 2003 – two passes

A pretty interesting lesson learned from organizations who have implemented Exchange 2003 is the way that Exchange 2003 gets backed up. For organizations that use the built-in Windows Backup utility that comes with Windows 2003 (and is also applicable for many 3rd party tape backup software programs based on similar use of Windows 2003 backup API technologies), the backup process may not be working as expected.

The issue is that if you setup the tape backup software to backup “the entire server” on a single backup process (which is a pretty common thing for people to do). The problem, if you review the Exchange LOG files, is that the log files aren't flushing night after night. There are two Microsoft Technical articles (820272 http://support.microsoft.com/default.aspx?scid=kb;EN-US;820272 and 820852 http://support.microsoft.com/default.aspx?scid=kb;EN-US;820852) that basically confirmed the problem. Although 820272 says to “either” backup as 2 separate routines, OR to put the EDBs on a separate drive; however you'll find that having the EDBs on separate drives than the system state / programs doesn't solve the problem, so you need to setup two separate routines to make this work (backup routines on an Exchange server: one to backup the C> and System State, and one to backup the Information Store Service)

The “reasoning” for this problem as stated in the Technical Articles is because Exchange 2003 backup uses the Volume Shadow Copy Service (VSS) to snapshot the data before it is backed up. With VSS enabled, all backup processes (system state, program volume, and databases) are flagged as “backup in progress” until the backup is complete. While the system successfully backs everything up, the Information Store does not flush the committed logs because the state of the server shows the system failed to backup successfully because of the VSS lock. By splitting the backup process into two processes, the system state / program volume backs up successfully, THEN the information store is backed up separately and completes successfully, thus flushing the logs.

I would call this a “bug” in the way the backup APIs are tracking completed state and would likely be fixed in a future update to Exchange 2003, but for now, at least with the built-in Windows Backup software, you need to kick off 2 separate backup routines.