This used to be my backup process. Five copies, one for each day of the week.
This used to be my backup process. Five copies, one for each day of the week.

I was reading Scott Hanselman’s post onThe Computer Backup Rule of Three, and I completely agree with him. If things are important, three copies are the minimum you should keep. I have had backups before, but I’ve found that when something breaks, like a tape drive or hard drive, I might not get to replace it right away. Usually this is procrastination, or as it’s more commonly known, laziness. During that window of opportunity, I’ve had Mr. Murphy strike. My inherent paranoia of having that second extra copy has saved me, both personally (at home) and professionally (at work).

All too often I run into DBAs that seem to trust and assume their backups and processes are very reliable. After setting up a backup process, usually to disk, and testing it with a restore on another system, they assume it will work in the future. It should, but there is always the chance something will fail at some point in time. There’s the chance that some hardware failure or software reconfiguration will cause an issue with your process. There’s also the simple chance that your I/O system might introduce corruption into your backup files.

If you aren’t regularly testing your processes, you can’t be sure they are working as they have in the past. The ideal environment would perform a restore of every backup file taken, every day, but that isn’t always possible. However restoring a random backup once every month or two will help you to ensure your backup, and restore, processes, have the best chance of succeeding when you actual need to perform them because of a disaster.

This isn’t hard to script and automate, but it is something you need to do periodically. However even if you automate restores of all your databases, make sure you still practice your manual skills regularly. Automation might not work in a disaster situation, but those quarterly practice sessions restoring a database to a point in time with a tail log might just relax you when a crowd in your cube is asking if the database will be back up soon.

Steve Jones

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