BackupPC-users

Re: [BackupPC-users] Filesystem corruption: consistency of the pool

2010-12-09 15:23:55
Subject: Re: [BackupPC-users] Filesystem corruption: consistency of the pool
From: Robin Lee Powell <rlpowell AT digitalkingdom DOT org>
To: "General list for user discussion, questions and support" <backuppc-users AT lists.sourceforge DOT net>
Date: Thu, 9 Dec 2010 12:21:53 -0800
On Thu, Dec 09, 2010 at 03:15:41PM -0500, Jeffrey J. Kosowsky wrote:
> Robin Lee Powell wrote at about 12:06:24 -0800 on Thursday,
> December 9, 2010:
>  > On Thu, Dec 09, 2010 at 03:03:37PM -0500, Jeffrey J. Kosowsky
>  > wrote:
>  > > Robin Lee Powell wrote at about 11:20:26 -0800 on Thursday,
>  > > December 9, 2010:
>  > >  > On Thu, Dec 09, 2010 at 09:53:25AM +0100, martin f krafft
>  > >  > wrote:
>  > >  > > also sprach Jeffrey J. Kosowsky <backuppc AT kosowsky DOT org>
>  > >  > > [2010.11.17.0059 +0100]:
>  > >  > > > I wrote two programs that might be helpful here:
>  > >  > > > 1. BackupPC_digestVerify.pl
>  > >  > > >    If you use rsync with checksum caching then this
>  > >  > > >    program checks the (uncompressed) contents of each
>  > >  > > >    pool file against the stored md4 checksum. This
>  > >  > > >    should catch any bit errors in the pool. (Note
>  > >  > > >    though that I seem to recall that the checksum only
>  > >  > > >    gets stored the second time a file in the pool is
>  > >  > > >    backed up so some pool files may not have a
>  > >  > > >    checksum included - I may be wrong since it's been
>  > >  > > >    a while...)
>  > >  > > 
>  > >  > > I did a test run of this tool and it took 12 days to run
>  > >  > > across the pool. I cannot take the backup machine
>  > >  > > offline for so long. Is it possible to run this while
>  > >  > > BackupPC runs in the background?
>  > >  > > 
>  > >  > > > 2. BackupPC_fixLinks.pl
>  > >  > > >    This program scans through both the pool and pc
>  > >  > > >    trees to look for wrong, duplicate, or missing
>  > >  > > >    links. It can fix most errors.
>  > >  > > 
>  > >  > > And this?
>  > >  > 
>  > >  > I don't know about the first one, but BackupPC_fixLinks.pl
>  > >  > can *definitely* be run while BackupPC runs.
>  > >  > 
>  > >  > For serious corruption, you may want to grab the patch I
>  > >  > posted a few days ago; it makes the run *much* slower, but
>  > >  > on the plus side it will fix more errors.
>  > > 
>  > > I would suggest instead using the version I posted last
>  > > night... It should be much faster though still slow and may
>  > > avoid some issues...
>  > 
>  > Well, I meant that version *plus* my patch. :D
> 
> My version does what your patch posted a couple of days does only
> faster & probably better (i.e. your version may miss some cases
> where there are pool dups and unlinked pc files with multiple
> links).

I repeat my assertion that you are my hero.  :)

-Robin

-- 
http://singinst.org/ :  Our last, best hope for a fantastic future.
Lojban (http://www.lojban.org/): The language in which "this parrot
is dead" is "ti poi spitaki cu morsi", but "this sentence is false"
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