Problem in refcountstore.py

Anthony netangel at gmail.com
Wed Jan 2 11:04:47 GMT 2013


Hi Lars,

After I checked my copied syslog after new failures, I saw nothing
concerning disk problem, so I think it's a software problem.
I deleted once again all my obnam repository in order to make a fresh
backup.
I tried twice. The first time it bugged (still the same "KeyError"
problem), without any relevant information in the syslog.
After that, I noticed that the obnam.log file was really big (> 700MB), so
I deleted it, deleted the repository again, and started once more the
backup.
That time it ended successfully... do you think the log file can cause any
problem when it's too big ?

I will test that now : deleting the log file before backing up each day.

2012/12/17 Anthony <netangel at gmail.com>

> Hi Lars,
>
> That's strange because after I had all those errors, I've erased once
> again all the files on my backup repository (because I thought, perhaps
> there has been a problem between the two different version of obnam I use=
d,
> due to the update proposed by my Ubuntu 12.04).
> Then, my backup script (which is mainly obnam
> --config=3D/home/user/.obnam.conf force-lock && obnam
> --config=3D/home/user/.obnam.conf backup /home/user && obnam
> --config=3D/home/user/.obnam.conf forget - with the root user -) worked e=
very
> days during one week more or less.
> And once again I had :
> 2012-12-07 23:58:53 INFO Backing up /home/user
> 2012-12-07 23:58:53 INFO VFS: baseurl=3D/home/user read=3D0 written=3D0
> 2012-12-08 00:01:19 INFO Unlocking client because of error
> 2012-12-08 00:01:19 INFO Unlocking shared trees because of error
> 2012-12-08 00:01:19 CRITICAL Traceback (most recent call last):
>   File "/usr/lib/python2.7/dist-packages/cliapp/app.py", line 169, in _run
>     self.process_args(args)
>   File "/usr/lib/python2.7/dist-packages/obnamlib/app.py", line 174, in
> process_args
>     cliapp.Application.process_args(self, args)
>   File "/usr/lib/python2.7/dist-packages/cliapp/app.py", line 419, in
> process_args
>     method(args[1:])
>   File
> "/usr/lib/python2.7/dist-packages/obnamlib/plugins/backup_plugin.py", line
> 275, in backup
>     self.repo.commit_client()
>   File "/usr/lib/python2.7/dist-packages/obnamlib/repo.py", line 473, in
> commit_client
>     self._really_remove_generations(self.removed_generations)
>   File "/usr/lib/python2.7/dist-packages/obnamlib/repo.py", line 573, in
> _really_remove_generations
>     remove_gens(remove_genids)
>   File "/usr/lib/python2.7/dist-packages/obnamlib/repo.py", line 560, in
> remove_gens
>     self.client.remove_generation(genid)
>   File "/usr/lib/python2.7/dist-packages/obnamlib/clientmetadatatree.py",
> line 292, in remove_generation
>     self.forest.remove_tree(tree)
>   File "/usr/lib/python2.7/dist-packages/larch/forest.py", line 125, in
> remove_tree
>     tree._decrement(tree.root.id)
>   File "/usr/lib/python2.7/dist-packages/larch/tree.py", line 601, in
> _decrement
>     self._decrement(child_id)
>   File "/usr/lib/python2.7/dist-packages/larch/tree.py", line 589, in
> _decrement
>     refcount =3D self.node_store.get_refcount(node_id)
>   File "/usr/lib/python2.7/dist-packages/larch/nodestore_disk.py", line
> 271, in get_refcount
>     return self.rs.get_refcount(node_id)
>   File "/usr/lib/python2.7/dist-packages/larch/refcountstore.py", line 76,
> in get_refcount
>     return self.refcounts[node_id]
> KeyError: 451470
>
> I attached the refcounts I had after that KeyError.
>
> Since that time, I continued to execute my script each night, and
> sometimes the "obnam --config=3D/home/user/.obnam.conf backup /home/user"
> command works, but then it's the "forget" command which bugs with a
> KeyError.
>
> I'm nearly certain it's not a disk problem as it's a new disk... but I
> will copy the /var/log/syslog before shuting down the computer in order to
> check that.
>
> Any other clues ?
>
> Thanks for your answer anyway !
>   Anthony
>
>
> 2012/12/14 Lars Wirzenius <liw at liw.fi>
>
>> Hi, Anthony,
>>
>> I'm sorry it's taken me so long to respond to you.
>>
>> On Wed, Nov 14, 2012 at 05:23:24PM +0100, Anthony wrote:
>> > Hi,
>> >
>> > I don't really understand, I've completely deleted my repository and
>> > completely backup again.
>> > It works greatly twice and the 3d time, it bugged again with the same
>> error
>> > :
>> ...
>> >   File "/usr/lib/python2.7/dist-packages/larch/refcountstore.py", line
>> 76,
>> > in get_refcount
>> >     return self.refcounts[node_id]
>> > KeyError: 253507
>>
>> This error means that Obnam is trying to get the reference count
>> for a B-tree node from disk, and when it does that, there is no reference
>> count for the B-tree node, and that crashes Obnam.
>>
>> This is a very weird error that I have not seen before.
>>
>> If you still have the backup repository, could you run "obnam fsck" to
>> see if that reports any problems? Thanks.
>>
>> --
>> http://www.cafepress.com/trunktees -- geeky funny T-shirts
>> http://gtdfh.branchable.com/ -- GTD for hackers
>>
>
>
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