Tuesday, December 07, 2004

Getting Dizzy Thinking about Circular Logging?

Here's the skinny. When SBS 2000 shipped, we shipped with circular logging disabled (meaning Exchange was going to do it's full logging). Our Product Support Folks (PSS) were struggling with the number of calls of people who run out of disk space. Why is this? No Exchange-Aware backup was being done on the box, and the log files will grow indefinitely. Finally, due to the nature of an SBS install (typically a single volume with everything on it) the DC and Exchange server would run out of disk space at the same time (since they are the same box).

This can spell out bad news.

So with SBS 2003, we did 2 things. First, we provided an inbox backup solution to make it easy for people who were scared of backup and didn't understand it to successfully setup a backup and actually do Exchange-Aware backups (yes, NTBackup is Exchange aware!). Second, we enabled circular logging out of the box (to prevent log files from growing out of control!), we re-enable it when you run the wizard, and never disable it again (even if you disable the SBS backup tools).

So what does this mean for you?

If you're using a 3rd party backup solution, that's Exchange-Aware, you're probably going to want to disable the circular logging to reap the full rewards of Exchange logging functionality. How do you do this? Well, you can run the SBS Backup wizard, then run it again and disable it. Or you can modify the setting directly. Simply:

  1. Open Server Management and expand Advanced Management, First Storage Group, Servers, {Servername}

  2. Right click on First Storage Group and choose Properties

  3. On the General tab, uncheck the Enable circular logging and choose OK

That's all there is to it. Now you're 3rd party backup application will tell Exchange to truncate the logs and you're all set.