[Borgbackup] "borg check --repair" problem

[Thomas Portmann]

Am 26.07.20 um 16:16 schrieb Joseph Hesse:
> I am using Linux with ext4 file system and the partition on the external 
> drive passed an "fsck" and "badblocks" test.

Did you look at the fsck output?

> I deleted the index for the repository and then did a "borg check 
> --repair",  and, even though there was a warning that this was an 
> experimental feature,
> I felt I had no other choice but to proceed.

Yes, exactly. This hint is only very, very honest, but you have no other 
chance in this situation, anyway. You can trust.

> I got the output below.
> There a 3 backups in this output and since the files in question that 
> are causing the error have very long names, I have replaced them with 
> FILE1, FILE2, ..., FILE6 and changed user names.

To be honest, since I never experienced this kind of damage, I can 
compare your report only with my experience with Borgbackup in general 
and with my understanding of its documentation.

Since your log says there are missing file chunks which have been 
replaced with all-zero chunks, your 6 files will now contain these 
chunks. So when you extract these files, they will be damaged / contain 
these holes. All other files and archives should be intact. But I cannot 
exclude that there is another data loss.

Apart from this, the three archives and the repository should be in a 
consistent state now.

 > I plan on deleting the 3 backups in the repository and hope for the
 > best.  Is this a good plan?  I prefer not but I can afford to lose the
 > entire repository since I have Borg backups on other repositories.

There is no need to remove the archives or the repo.---You can confirm 
this if you run "borg check" (without "--repair") again. So you're done.

A good plan would be to finding the root cause, if possible, and deduce 
countermeasures for the future.


Cheers
Thomas