Thursday, March 13, 2008

Windows Server 2008 & Exchange Backup

So the Exchange Team was kind enough to write up a long blog post regarding Windows Server Backup included with Windows Server 2008.

However, some of the comments in this post need a little explaination, specifically around the "Exchange Aware Backup". The post mentions that the included Windows Server Backup is not aware of Exchange. This is in fact TRUE! Un-like NTBackup that would "light-up" Exchange backup and recovery features when Exchange was installed, the Windows Server Backup acts exactly the same way regardless of if Exchange is installed or not.

What I mean by this is the included backup application is VSS (Volume Snapshot Service) aware. Exchange 2007 provides a "VSS writer":

Try this at a an "elevated" command prompt: vssadmin list writers
What do you get?
Writer name: 'Microsoft Exchange Writer'
Writer Id: {76fe1ac4-15f7-4bcd-987e-8e1acb462fb7}
Writer Instance Id: {b2e17dae-6a8c-404c-a2b5-ebd4aa3a6277}
State: [1] Stable
Last error: No error
Among others...

When a Windows Server Backup is initiated, the backup application involks all of the VSS writers on the system, to prepare, and clean-up their specific application for backup. For Exchange, this includes, ensuring the database is consistent and trimming the Exchange log files after the database has been writen to the backup disk. Exchange's VSS writer does this, not the backup application.

This is not magic, but just how VSS backups work. *Any* application that installs a VSS writer correctly, will be correctly managed by the built in Windows Server Management program, regardless if the backup solution is aware of the install or not.

If you're familiar with the old (and I mean old!) NTBackup solution, Exchange provided "Streaming APIs" to stream the database out and into the database for backup purposes. Windows Server 2008 Backup does NOT take advantage of these, even though they are still available for 3rd party backup applications.

So, you SBS'rs, can rest assured Exchange is being backed up correctly on Windows Server 2008. You'll have to wait until Windows Small Business Server 2008 releases (or jump in on the Beta, when it's available) to see the restore in action. ;o)


Anonymous said...

I have been using Windows backup to backup Exchange 2007 the Best Practices Analyzer indicates I have never preformed a full backup. The log files are also not being removed after a backup. Is this normal behavior?

Sean Daniel said...

What Backup application are you using? Typically the backup application if it's Exchange aware, or uses VSS, should truncate the log files for you, indicating you have a full backup Make sure you don't run out of disk space with log files and the store while you figure this out.

Foo said...

But according to the Exchange Team blog:

"but there are additional requirements for Exchange backups and restores beyond using the VSS Framework; for example, checking the database and log files for corruption during backups is not part of the VSS Framework and it is not performed by Windows Server Backup."

So, how is that addressed?

Sean Daniel said...

We included a recovery file, which will be available also late this year for standard users.

Anonymous said...

I have been using Windows Server Backup in SBS 2008 to backup Exchange 2007, but backup claims the exchange backup is in error due to problems with database consistency checks. I have used eseutil against the database and it comes up clean, so not sure why this would occur. Exchange MMC also states the database has never been backed up. Looking at the backup data(through the restore process), all Exchange files (logs, edb, etc.) are present. Seems like there is a disjunct somewhere???

Sean Daniel said...

Hi there,

Have you used the native backup to backup the exchange database? have you run the Exchange BPA?