RAID is not a backup techology.
Posted Fri, 02 Jan 2009
Today, I heard about journalspace going down because it lost data and didn't have backups. While I don't use the service, so it doesn't affect me, the failure they experienced makes for a great case study in false data security and backups. From the front page of journalspace.com:
Here is what happened: the server which held the journalspace data had two large drives in a RAID configuration. As data is written (such as saving an item to the database), it's automatically copied to both drives, as a backup mechanism.RAID is not a backup solution. RAID can get you, depending on the configuration, better throughput and/or better data reliability. If you lose a drive in some raid configurations, the system can continue working normally without that drive. Backups should copy data somewhere other than the machine hosting the original data. The page goes on:
The value of such a setup is that if one drive fails, the server keeps running, using the remaining drive. Since the remaining drive has a copy of the data on the other drive, the data is intact. The administrator simply replaces the drive that's gone bad, and the server is back to operating with two redundant drives.
So, after nearly six years, journalspace is no more.After almost 6 years nobody had a cron job that backed up data to somewhere offsite (or a more complex backup system)? Ouch! My condolences to journalspace and its users on the loss.
Losing important data unexpectedly will sting you bad if you don't have appropriate backups. The only thing to do is learn from this mistake and move on, accepting the consequences of the loss.
This isn't the first website I've heard of having to shutdown because they permanently lost data. Learn from their mistakes, keep backups of your stuff!