Re: [linux-lvm] LVM hangs

["Alexander 'Leo' Bergolth" <leo@strike.wu.ac.at>]

Hi!

On 11/13/2017 03:51 PM, Zdenek Kabelac wrote:
> Dne 13.11.2017 v 14:41 Alexander 'Leo' Bergolth napsal(a):
>> I have a EL7 desktop box with two sata harddisks and two ssds in a
>> LVM raid1 - thin pool - cache configuration. (Just migrated to this
>> setup a few weeks ago.)
>>
>> After some days, individual processes start to block in disk wait.
>> I don't know if the problem resides in the cache-, thin- or raid1-layer
>> but the underlying block-devices are fully responsive.
>>
>> I have prepared some info at:
>> �� http://leo.kloburg.at/tmp/lvm-blocks/
>>
>> Do the stack backtraces provide enough information to locate the source
>> of the blocks?
>>
>> I'd be happy to provide additional info, if necessary.
>> Meanwhile I'll disable the LVM cache layer to eliminate this potential
>> candidate.
> 
> It would be probably nice to see the result of 'dmsetup status'


OK. Will be included next time.


> I'd have guessed you are probably hitting� 'frozen' raid state
> which is unfortunate existing upstream bug.

Are you talking about RH bug 1388632?
https://bugzilla.redhat.com/show_bug.cgi?id=1388632

Unfortunately I can only view the google-cached version of the bugzilla
page, since the bug is restricted to internal view only.

But the google-cached version suggests that the bug is mainly hit when
removing the raid-backed cache pool under IO.

I my scenario, no modification (like cache removal) of the lvm setup was
done when the blocks occured.

Cheers,
--leo
-- 
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