The two main reasons I can think of for taking backups seems to be taken care of when I use both snapshots and RAID together with btrfs. (By RAID here, I mean RAID1 or 10)
- Accidental deletion of data: Snapshots covers this case
- Failure of a drive and bit rot
- Complete failure: RAID covers this case
- Drive returning bad data: RAID + btrfs' error correcting feature covers this case
So as an on-site backup solution, this seems to work fine, and it doesn't even need a separate data storage device for it!
However, I have heard that both RAID and snapshots aren't considered proper backups, so I'm wondering if I have missed anything.
Aside from btrfs not being a mature technology yet, can you think of anything I've missed? Or is my thinking correct and this is a valid on-site backup solution?
Best Answer
No, it's not.
What happens when your filesystem or RAID volume gets corrupted? Or your server gets set on fire? Or someone accidentally formats the wrong array?
You lose all your data and the not-real-backups you thought you had. That's why real backups are on a completely different system than the data you're backing up - because backups protect against something happening to the system in question that would cause data loss. Keep your backups on the same system as you're backing up, and data loss on that system can impact your "backups" as well.