Re: [Duplicity-talk] Recovering corrupted incremental backup

[edgar . soldin]

On 29.07.2021 16:12, Pierre-Alexis Ciavaldini via Duplicity-talk wrote:
> Hi,
>
> I have a situation where an extremely important file is in a corrupted 
> incremental backup. My guess to what happened is that the last recorded 
> incremental backup was too heavy and could not finish writing to disk because 
> it was full, so the GUI says invalid hash.
>
> I've followed the worst case manual extraction procedure for the latest full 
> backup, but now I need to do the same with incremental.
>
> The latest incremental backup, which should contain the file (if the backup 
> stopped after copying this file), has 24 volumes finishing with :
>
> duplicity-inc.20210206T080811Z.to.20210207T090128Z.vol24.difftar
>
> It has a .manifest but no .sigtar
>
> Should all incremental backups be extracted and added, or only the latest one 
> ? Any other advice to maximize my luck ?
>

hi Pierre-Alexis,

indeed you need to simulate duplicity restore process, which is restoring the 
first version of a file and applying all changes from later incrementals to it. 
in your case it might be possible to retrieve the file via

  duplicity restore --ignore-errors --file-to-restore <relpath> [--time time] 
source_url restore_directory

see man page http://duplicity.nongnu.org/vers8/duplicity.1.html
"
--ignore-errors
Try to ignore certain errors if they happen. This option is only intended to 
allow the restoration of a backup in the face of certain problems that would 
otherwise cause the backup to fail. It is not ever recommended to use this 
option unless you have a situation where you are trying to restore from backup 
and it is failing because of an issue which you want duplicity to ignore. Even 
then, depending on the issue, this option may not have an effect.
Please note that while ignored errors will be logged, there will be no summary 
at the end of the operation to tell you what was ignored, if anything. If this 
is used for emergency restoration of data, it is recommended that you run the 
backup in such a way that you can revisit the backup log (look for lines 
containing the string IGNORED_ERROR).

If you ever have to use this option for reasons that are not understood or 
understood but not your own responsibility, please contact duplicity 
maintainers. The need to use this option under production circumstances would 
normally be considered a bug.
"

good luck.. ede/duply.net