Software entrepreneur Joel Spolsky says that's a good start, but only part of it:
[L]et’s stop talking about “backups.” Doing a backup is too low a bar. Any experienced system administrator will tell you that they have a great backup plan, the trouble comes when you have to restore.
And that’s when you discover that:
- The backed-up files were encrypted with a cryptographically-secure key, the only copy of which was on the machine that was lost
- The server had enormous amounts of configuration information stored in the IIS metabase which wasn’t backed up
- The backup files were being copied to a FAT partition and were silently being truncated to 2GB
- Your backups were on an LTO drive which was lost with the data center, and you can’t get another LTO drive for three days
- And a million other things that can go wrong even when you “have” “backups.”
The minimum bar for a reliable service is not that you have done a backup, but that you have done a restore.
As someone who's got reliable, clockwork backups running, and has had them fail for one of the reasons Spolsky listed (and others that he didn't), I think this is tremendously good advice.