BackupPC-users

Re: [BackupPC-users] High Backup Data Volumes After Re-adding an Excluded Directory

2010-07-19 11:51:39
Subject: Re: [BackupPC-users] High Backup Data Volumes After Re-adding an Excluded Directory
From: Josh Malone <jmalone AT nrao DOT edu>
To: "General list for user discussion, questions and support" <backuppc-users AT lists.sourceforge DOT net>
Date: Mon, 19 Jul 2010 11:49:16 -0400
On Sun, 18 Jul 2010 10:24:08 -0400, "Norbert Hoeller" <nhoeller AT sinet DOT ca>
wrote:
> While trying to diagnose the high backuppc data volumes issue posted to
> the mailing list on June 14th, I had excluded a directory structure
> containing about 140MB of data. I removed the exclude once Craig had
> provided a fix for File::RsyncP and noticed that backup volumes jumped
by
> about 150MB. Tracing suggested that all the files in the previously
> excluded directory structure were being backed up on every incremental
> backup, even though the content of the files was unchanged (the first
> incremental backup after the directory was added indicated that backuppc
> had found the file in the backup pool). 
> 
> Although the contents of the files had not changed, I had 'touch'ed the
> files during the period where the directory structure has been excluded
> so that Google Sitemap would index them . It seems that the backuppc
> incremental backup got confused and repeatedly selected the files for
> backup even though the file date was no longer changing.  
> 
> File::RsyncP/rsync should have determined that the contents of the files
> were identical to the pool copy. Verbose logging suggests that checksums
> were exchanged, but rsync did nothing with them (the remote system
> reported false_alarms=0 hash_hits=0 matches=0). The reason is not clear.
> I had enabled checksum caching at one point but disabling checksum
> caching it did not change the symptoms. 
> 
> The problem was 'fixed' by doing a full backup. It appears that this
> caused rsync to properly compare checksums and backuppc updated the file
> date - the next incremental backup did not check the files that
> previously had been copied in full. I 'touch'ed one of the files and
> verified that the next incremental backup checked the file but rsync
> found no changed blocks.

During incremental backups, backuppc will backup any files not already in
the previous full, IIRC. Also, unless you change it in the config, backup
dump levels don't increment on each successive incremental; each
incremental is a "level 1" meaning "Backup all files changed since the
previous full".

You can change "IncrLevel" in the config to "1, 2, 3, 4, 5, 6, 7" or such
to change this behaviour.

-Josh


-- 
--------------------------------------------------------
       Joshua Malone       Systems Administrator
     (jmalone AT nrao DOT edu)    NRAO Charlottesville
        434-296-0263         www.cv.nrao.edu
        434-249-5699 (mobile)
BOFH excuse #81:

CPU-angle has to be adjusted because of vibrations
coming from the nearby road
--------------------------------------------------------

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