XFS Freezing occasionally hangs

[Ryan Campbell]

In #xfs, bpm recommended I run echo t > /proc/sysrq-trigger. Here's the
output of that command on the host with the stuck xfs_freeze. :
https://gist.github.com/4636507


On Fri, Jan 25, 2013 at 11:08 AM, Ryan Campbell <ryan.campbell at gmail.com>wrote:

> Is there any additional information I can provide to debug this issue? We
> are seeing it quite often.
>
>
> On Thu, Jan 24, 2013 at 9:38 AM, Ryan Campbell <ryan.campbell at gmail.com>wrote:
>
>> We use XFS on EC2 EBS running on Arch Linux (kernel 3.6.7-1-ARCH). Before
>> we take an EC2 snapshot, we call xfs_freeze on the mount so that we can
>> have a consistent snapshot.
>>
>> On instances running for around 30 days, we see the XFS freeze hang,
>> resulting in a skyrocketing load (but not CPU). We can't kill the
>> xfs_freeze process. The only route available is usually to force a reboot
>> of the server without cleaning unmounting.
>>
>> There are backtraces in dmesg complaining both of hung xfs processes, and
>> hung java processes. https://gist.github.com/3d46830eac52df44d30f
>>
>> Is this a known issue? We call xfs_freeze quite often on thousands of XFS
>> volumes, so I wouldn't be surprised if we have encountered an edge case
>> considering how often we do this.
>>
>> Any help appreciated. I'm recampbell on #xfs/freenode.
>>
>> Thanks,
>> Ryan
>>
>
>
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