Section 2.8. Monitoring Your Backups

2.8. Monitoring Your Backups

If you are not monitoring your backups, they are not doing what you think they are doingguaranteed. This is one pot that will not boil if you don't watch it. Every backup should have a log that is examined daily. This can be automated as well. Here are some examples:

Give me a summary.

dump gives a whole bunch of messages that I couldn't care less about, Pass I, Pass II, % done, and so on. When I'm monitoring the dump backups of hundreds of drives or filesystems, most of that is so much noise. What I really want to see is what got dumped, where it went, when it went, what level it was, and the ever-popular DUMP IS DONE message. To get a summary of just these lines, the first thing I do is use grep -v to exclude the phrases I don't want, leaving only a few lines. This is much easier to review. This technique can also be applied to other Unix, Linux, and Mac OS backup commands.

Show me anything weird.

You can do this in either of two ways. If you know the phrases that show up when things go wrong, grep for those. Another way is to use grep -v to remove all lines you're expecting and see what's left. If there's nothing, great! If there are lines left over, they are probably errors. You may see lines such as I/O error, Write error, or something else you don't like to see in your backups.

If you want to apply this to a Windows task, you need to take advantage of some Unix emulators, such as Cygwin, UWIN, or GnuWin32, to allow you to run grep and other shell commands on a Windows system.

2.8.1. You Can Always Make It Better

I don't care how good your backups are; they can always be better. You could spend every waking hour tweaking and improving every piece of your backup program and know everything there is to know about backups, and they could still be better. My backups will never be good enough. There's always a new bell or whistle on some other backup package, a bigger or smarter jukebox, a faster backup drive, or some scenario I thought of that I'm not covering. You must realize, however, that every change you make has a potential for data loss. A common thread that you will find in this book is that every time the human being enters into the equation, things can go wrong. You may be the best shell or Perl hacker in the world, and you will still make mistakes.

2.8.2. If It's Not Baroque, Don't Fix It

Baroque needed fixing. Come on! One constant tempo? And the harpsichord? It had to go. Thankfully, Bartolomeo Cristofori invented the piano in 1709 and gave us an instrument that could play loud (fortissimo) and quiet (piano)hence its name. Shortly after that, the Classical period started, and music started changing in tempo and feeling.

But if it's not broken, don't fix it! You've heard it before, but given the risk that each change makes, it goes double in the backup world. As you read this book or some magazine, or talk to other administrators, you will undoubtedly come up with a list of things that you wish you were doing. Concentrate on the holes, or scenarios that your backup and recovery plan just does not cover. Worry about the fact that none of your volumes are stored off-site before you think about working on that cool menu program you've been wanting to write for your restores. Make sure you're covering all the bases before you start redecorating the stands. Before you consider making a new change, ask yourself if something else is more important and if the change is really necessary and worth the risk.