I’ve written many times about the need to keep good backups – not just one backup, but multiple copies of backups. I had an experience last week that proves the point.
I keep three sets of backups:
- My most critical files are backed up automatically every two hours to Mozy, an online backup service.
- Almost all data files are backed up automatically starting at 1:00 AM every day to a 500–gigabyte device that is on my in-home network. This device acts like a 500-gigabyte disk drive on the network. I back up the same files to the device that I also back up on Mozy, plus many more.
- About once a month, I manually back up critical files to a DVD-ROM disk and take them to the office, storing them in a desk drawer there.
Some time last week, the automated middle-of-the-night backups started failing. A bit of investigation revealed that the network attached storage device was giving errors. I found that one of the disk drives in the storage device was spitting out read errors and write errors. Some of the files stored there were accessible while others were not. Had that been my only backup, and had I suffered a problem on the primary system(s), I could have been in trouble!
However, this is one case where I practice what I preach. I had the more critical files also backed up on Mozy and on a DVD disk at the office. While the loss of one set of backups was inconvenient, it turned out to be “no big deal.”
I have now reformatted the disk drive in question and have made a new, full backup to the NAS device. I’ll be keeping a close eye on it for a while to see if the errors re-appear. However, I have the added – and sometimes critical – insurance of other backups as well.
How many copies do you have of your backups?