* Re: Lots of trouble hanging when rm files with many extents
@ 2013-10-20 14:51 Tomasz Chmielewski
2013-10-21 3:40 ` John Goerzen
0 siblings, 1 reply; 3+ messages in thread
From: Tomasz Chmielewski @ 2013-10-20 14:51 UTC (permalink / raw)
To: linux-btrfs@vger.kernel.org, jgoerzen
> but I am not sure if that was the right thing to do. This is
> producing OOM issues and leading to system crashes (including
> eventual panics) with such alarming frequency that I wonder if
> perhaps there is something different about my setup than others.
FYI, I'm seeing similar / random hangs on systems with btrfs,
compress-force=zlib, qgroups enabled. The systems have 32 GB RAM.
Sometimes, I can review old logs (after force reboot) and see OOM,
allocation failures and such.
The scenario there are snapshots, rsync with --inplace flag, which can
fragment files a lot.
I'll do some more tests with lots of extents to see if it's
reproducible here as well.
--
Tomasz Chmielewski
http://wpkg.org
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: Lots of trouble hanging when rm files with many extents
2013-10-20 14:51 Lots of trouble hanging when rm files with many extents Tomasz Chmielewski
@ 2013-10-21 3:40 ` John Goerzen
2013-10-25 13:41 ` rm with quotas can cause panic (was Re: Lots of trouble hanging when rm files with many extents) John Goerzen
0 siblings, 1 reply; 3+ messages in thread
From: John Goerzen @ 2013-10-21 3:40 UTC (permalink / raw)
To: Tomasz Chmielewski; +Cc: linux-btrfs@vger.kernel.org
On 10/20/2013 09:51 AM, Tomasz Chmielewski wrote:
>> but I am not sure if that was the right thing to do. This is
>> producing OOM issues and leading to system crashes (including
>> eventual panics) with such alarming frequency that I wonder if
>> perhaps there is something different about my setup than others.
> FYI, I'm seeing similar / random hangs on systems with btrfs,
> compress-force=zlib, qgroups enabled. The systems have 32 GB RAM.
> Sometimes, I can review old logs (after force reboot) and see OOM,
> allocation failures and such.
>
> The scenario there are snapshots, rsync with --inplace flag, which can
> fragment files a lot.
>
> I'll do some more tests with lots of extents to see if it's
> reproducible here as well.
>
>
Interestingly, I've generally had qgroups enabled here as well, possibly
on all of these systems. Could that be the culprit?
^ permalink raw reply [flat|nested] 3+ messages in thread
* rm with quotas can cause panic (was Re: Lots of trouble hanging when rm files with many extents)
2013-10-21 3:40 ` John Goerzen
@ 2013-10-25 13:41 ` John Goerzen
0 siblings, 0 replies; 3+ messages in thread
From: John Goerzen @ 2013-10-25 13:41 UTC (permalink / raw)
To: linux-btrfs
John Goerzen <jgoerzen <at> complete.org> writes:
>
> On 10/20/2013 09:51 AM, Tomasz Chmielewski wrote:
> > I'll do some more tests with lots of extents to see if it's
> > reproducible here as well.
> >
> >
> Interestingly, I've generally had qgroups enabled here as well, possibly
> on all of these systems. Could that be the culprit?
Updating the subject here, because it seems increasingly likely that quotas
are the problem causing OOM panics.
I was able to reproduce the problem on a test filesystem with quotas
enabled. After quotas were disabled and the system was rebooted, the
problem no longer occurred. The dangerous combination seems to be many
extents plus quotas.
Sadly, quotas are the only way to have btrfs keep track of how much space
subvols are using, so it's very useful to be able to use that feature.
I also noted this at https://bugzilla.kernel.org/show_bug.cgi?id=63071
John
^ permalink raw reply [flat|nested] 3+ messages in thread
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2013-10-20 14:51 Lots of trouble hanging when rm files with many extents Tomasz Chmielewski
2013-10-21 3:40 ` John Goerzen
2013-10-25 13:41 ` rm with quotas can cause panic (was Re: Lots of trouble hanging when rm files with many extents) John Goerzen
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