I'm curious about something here.
First, some background. I recently set up a backup system I really, really like. It's on a Linux fileserver, no netapps in this picture. It's backing up c. 60GB of disk, a single root drive and a 50GB RAID-5 with a hot spare, to another RAID-5 set, about 130GB, with no hot spare. I have a cronjob set to email me if a drive drops out of the set. I backup with a script that replicates all the data to be saved onto the backup raid set, using rsync, with the --backup-dir option to save anything that's been changed or deleted; then it takes all those changed-or-deleted files and bzip2s them into timestamped archives. When the backup partition gets over 90% full it commences deleting those bzip2-ed archives, starting with the oldest, until it's back down under 80% full. This gives me months of coverage and I never have to change a tape, and the cost of the drives is less than the cost of a suitable capacity tape drive to back up 60GB of data.
So anyway, enough with background, the question is, how come I don't hear anyone advocating using Netapp's snapshots as a backup strategy? Netapps don't lose data; it's not like WAFL or Netapp's RAID or any other bits are so bug-ridden that they don't do their job.
And you can buy a _Load_ of drives for what a heavy-duty industrial-strength DLT jukebox costs. Especially when you factor in the setup time, and the re-setup time every time it breaks. The Exabyte 8200 was the only tape drive I ever set up that didn't die before I switched jobs; seems like MTBF for a drive writing a tape a day is well under a year, at least in my experience in the last 6 years or so. Bleech.
-Bennett