Backups Need Backups
This week I’ve decided to cover something more in the style of a PSA than dealing with configurations and technical quirks that help speed up Microsoft SQL servers. The reason for the change of pace is from what I’ve been observing lately. It’s not pretty.
Backups end up being neglected. I’m not just pointing fingers at the primary backups, but where are the backup’s backups? The issue here is – what happens when the primary backups accidentally get deleted, become corrupt, or the entire disk ends up FUBAR? This happens more often than people realize. A disaster recovery plan that doesn’t have primary backups replicated to an offsite network or the very least in an isolated location is a ticking time bomb.
A healthy practice for the primary backups is to verify the integrity of backups after they complete. You can have Microsoft SQL Server perform checksum validation before writing the backups to media. This way if the checksum value for any page doesn’t exactly match that which is written to the backup, you’ll know the backup is trash. This can be done via scripts, jobs, or via manual backups. Look for the “Media” tab when running a backup task in SQL Server Management Studio. The two boxes to enable are “Verify backup when finished” and “Perform checksum before writing to media”.
It’s true we’re adding extra overhead here and might take backups a bit longer to finish. But I’ll leave it up to you to decide if the extra time is worth having a working backup you can trust to restore your database or a broken backup wasting precious resources. For the sake of reliability, if you decide time is more important, then at least have a script perform these reliability checks on a regular basis or schedule regular restores to make sure they even work.
If you follow this advice you can rest easy knowing your data can survive multiple points of failure before anything is lost. If the server room goes up in flames, you can always restore from the backups offsite. If you need help finding a way to have backup redundancy, a script to test backup integrity, or questions about anything I covered feel free to reach out. Any questions, comments, or feedback are always appreciated! Leave a comment or send me an email to firstname.lastname@example.org for any SQL Server questions you might have!