As I write this column, I cannot help but reflect on the irony of just having wiped out a month's worth of data. In the spirit of this article, I was fiddling around with backups on my web server, and I managed to accidentally delete most of /var/ and all of the /home/ directory. This wouldn't have been so bad if I hadn't kept the daily backups in /home/backups/. Oops.

Backing Up Doesn't Always Mean You Have Backups

If your data isn't available, or the systems to process and serve it aren't available, you have a problem. In the case of my web server, the missing /var/ and /home/ render it pretty much useless. It serves 404s and that's pretty much it. To make sure data is available, you need to back it up. Seems simple right? In reality most of us (myself included) get it wrong, and although we go through the motions of making a backup, what we're really doing is just copying the data somewhere else that is equally vulnerable to loss.

In my case, I made a classic mistake of storing my backups on the same system that the data being backed up is on, and to make things worse, I actually kept it in a commonly accessed directory. Not that this would have mattered. Because the server only has one hard drive, I am only a single disk failure away from complete data loss no matter how much I back my data up locally on the server. Even if I were to install a second hard drive in the machine, it's still all too easy for a single event (bad drive controller, attacker wiping the system, fire, flood, power supply going bonkers, theft, etc.) to wipe out more than one hard drive.

[...]