Re: [BackupPC-users] First major backupPC problem - corrupted backup?

[Craig B. <cba...@us...>]

Patrick Friedel writes:

> I've been running BackupPC for about a month now, and everything's been 
> peachy. This morning I notice Nagios is grousing that my BackupPC pool 
> partition is getting full, so I go check, and I see that the last 
> night's backup for one of the hosts looked like this:
> 
> Existing files | New Files
> Backup# Type Comp Level Size/MB Comp/MB Comp | Size/MB Comp/MB Comp
> 36 full 3 15432.9 9763.2 36.7% | 12.8 1.1 91.4%
> 37 incr 3 6783.5 4501.0 33.6% | 12295.0 12127.5 1.4%
> 
> So normally I back up less than 100 megs from that host, last night it 
> only found around a third of the files as existing, and made 12 new 
> gigs, huh?

That does look strange.  Notice also that the 12G of new files
don't compress much at all, wheresa the 15G of previous existing
files managed an average of 37%.

> Ok, maybe a user decided to offload all his MP3s to his home 
> directory, so I check the archives, and something ugly shows up in the 
> error log for this host:
>
> Contents of file /var/lib/backuppc/pc/localhost/XferLOG.37.z, modified 
> 2005-05-04 04:10:19 (Extracting only Errors)
> Running: /usr/bin/env LC_ALL=C /bin/tar -c -v -f - -C /opt/niord-home 
> --totals --newer=2005-05-03\ 01:37:31 --exclude=./dvd_source .
> Xfer PIDs are now 29112,29111
> /bin/tar: Substituting 1969-12-31 17:59:59 for unknown date format 
> `2005-05-03\\ 01:37:31'

This error is because you are backing up the local host, but
the incremental date is being shell escaped for use with ssh.
So instead of this:

    $Conf{TarFullArgs} = '$fileList+';
    $Conf{TarIncrArgs} = '--newer=$incrDate+ $fileList+';

you should use this:

    $Conf{TarFullArgs} = '$fileList';
    $Conf{TarIncrArgs} = '--newer=$incrDate $fileList';

The effect will be that tar will do a full backup instead
of an incremental backup.  So the main penalty is a slower
incremental backup and more server activity.  The backups
should still be fine.

> [normal backup errors dropped, just permissions problems usually]
> tarExtract: Tu?êU>??aUw]йVFÏKÊÃîQVDh03Á%¤\6+RyjR£ØEx@ÿCL?W&

Hmmm, I have no idea why BackupPC_tarExtract would write this
gibberish.

In any case, back to the original issue of the 12GB of new files
that aren't very compressible: you should look through the XferLOG
file to see which files appear to be new, and check them on the
client versus what was in backup #36.

Maybe there was some disk corruption or wholesale replacement of
files by that user.

Craig