[OpenAFS] files missing from incremental vos restore

[Christoph Scheurer]

Hello,

> > at our site we are using OpenAFS to serve home-directories for about 60
> > users. On Oct 27. we had a hardware failure on an AFS fileserver partition and
> > had to restore volume dumps from our backup. The restore procedure finished
> > succesfully but when we checked the restored volumes we had to realize that
> > some files were missing. Closer inspection showed that these files were
> > restored from the most recent full dumps but then removed by restoring the
> > subsequent incremental dumps, even that the respective files had not been
> > removed between dumps from the original volumes. Has anyone else
> > encountered/solved this problem before?
> 
> Did you remember to use the "-overwrite incremental" switch when doing
> the incremental restore?
Yes, the incremental dumps were restored with that option. And the list of
files that are missing is quite strange. Some of them have been recently
(i.e. after the last full dump) modified, others have not been modified in a
long time. There is no clear pattern visible. Is there a tool to inspect the
dumped information (especially the incremental dumps) without restoring the
dump temporarily to a volume? Would it be better to salvage the RW volumes
every time before backup/dump, even if their status seems not to require that?

> You are doing things the right way.  You don't want to backup the RW
> volume so that it stays available for the user.  The RO .backup volume
> both provides a way for you to backup files without interupting
> service and allows you to make the previous night's backup available
> at all times [often by mounting the volume somewhere, such as a
> .OldFiles mountpoint in a user's directory].
That is exactly what we do.

Loosing files on restoring the backup is quite unacceptable and we would have
to look into a different backup solution if the volume backup/dump is not
reliable. But then we would loose all the AFS ACL information etc.

Regards,

Christoph

-- 
Christoph Scheurer                                  GnuPG key Id: 0x6128C6B6

contact:   http://www.theo.chemie.tu-muenchen.de/homepages/scheurer/