Does check complain about
pack <...> not referenced in any index or
pack <...> does not exist, before all those
blob not found in index errors?
Which backend do you use to store your backup repository? Did you run
check some time before? Did anything unusual happen to your restic runs lately? Do / How often do you run
<edit>Just noticed your Github issue: Do you use AWS S3 or just an S3-compatible service? But I guess S3 should have enough provision to avoid data corruption. </edit>
You can probably find the damaged snapshots by running
restic rebuild-index to repair the damaged index and then run
restic stats --mode blobs-per-file which should complain about the snapshots with missing data (the mode is important here). You can also try out whether
restic backup --force ... recovers some of the missing blobs. But if its an option for you to wait a bit with repairing the repository, then I’d like to try to debug this a bit further.
I agree that the means to repair damaged repository are a bit lacking, but that’s primarily because restic goes to great lengths to avoid that such errors even occur. It is up to now unclear whether the damaged repositories are the result of hardware/operating system errors or of a tiny bug in restic. It’s rather hard to analyze as these damaged repositories only show up every now and then, but without any clear leads yet.