Why Mirroring Is Not a Backup Solution
Found on Slashdot on Thursday, 01 January 2009
Journalspace.com has fallen and can't get up. The post on their site describes how their entire database was overwritten through either some inconceivable OS or application bug, or more likely a malicious act. Regardless of how the data was lost, their undoing appears to have been that they treated drive mirroring as a backup and have now paid the ultimate price for not having point-in-time backups of the data that was their business.
I facepalmed real hard when I read on their site that the data is "automatically copied to both drives, as a backup mechanism". Although I understand the throubles they are in all too well, I don't feel sorry for them at all. I can't imagine how many times I've told people that mirroring is not a backup. Most of them won't learn until they went through it all. A USB drive costs just a few dollars. One would think at least that's an investment you're willing to make to safe your company. Granted that's not a perfect solution, but way better than nothing. Congrats to losing your six year old company because of an error any capable first term IT student could have protected you from. Now repeat: a RAID is not a backup.