I am quite worried about losing information and not being able to recover it from the backups, so I am trying to nail the best automated way to make sure the backups are good.
Restic comes with a check command, that according to the documentation here has this two “levels”:
- Structural consistency and integrity, e.g. snapshots, trees and pack files (default)
- Integrity of the actual data that you backed up
In plain words, I understand this as: The data you uploaded to the repository is still that data.
Now my question is, do you think this is enough to trust the backups are right?
I was thinking about restoring the backup in a temporary location and running diff on random files to check the files match the source, but I don’t know if this is redundant now.
How do you make sure you can trust your backups?
That isn’t as useful as you would think. If your computer fails there are high odds you will restore to a fresh install of a newer OS and newer software/services versions. Which means that you really want/need to also test data/config migration.
OTOH, if you have backups odds are the data is there even if you never tested them. Testing you can restore is mostly about do you have everything backed up. Your backups can pass all the validation but if you accidentally configured them to only backup /tmp (or something else worthless) you may as well not have backups. Thus you should test that you can do a full restore just to make sure that the data you want is all there. I generally trust that backup software can restore all the data you pointed it at without problems even if you didn’t test them - but I don’t trust that you (or I) configured them to backup the right things.