[gpfsug-discuss] strange waiters + filesystem deadlock
Sven Oehme
oehmes at gmail.com
Fri Mar 24 17:41:10 GMT 2017
ok, that seems a different problem then i was thinking.
can you send output of mmlscluster, mmlsconfig, mmlsfs all ?
also are you getting close to fill grade on inodes or capacity on any of
the filesystems ?
sven
On Fri, Mar 24, 2017 at 10:34 AM Aaron Knister <aaron.s.knister at nasa.gov>
wrote:
> Here's the screenshot from the other node with the high cpu utilization.
>
> On 3/24/17 1:32 PM, Aaron Knister wrote:
> > heh, yep we're on sles :)
> >
> > here's a screenshot of the fs manager from the deadlocked filesystem. I
> > don't think there's an nsd server or manager node that's running full
> > throttle across all cpus. There is one that's got relatively high CPU
> > utilization though (300-400%). I'll send a screenshot of it in a sec.
> >
> > no zimon yet but we do have other tools to see cpu utilization.
> >
> > -Aaron
> >
> > On 3/24/17 1:22 PM, Sven Oehme wrote:
> >> you must be on sles as this segfaults only on sles to my knowledge :-)
> >>
> >> i am looking for a NSD or manager node in your cluster that runs at 100%
> >> cpu usage.
> >>
> >> do you have zimon deployed to look at cpu utilization across your nodes
> ?
> >>
> >> sven
> >>
> >>
> >>
> >> On Fri, Mar 24, 2017 at 10:08 AM Aaron Knister <
> aaron.s.knister at nasa.gov
> >> <mailto:aaron.s.knister at nasa.gov>> wrote:
> >>
> >> Hi Sven,
> >>
> >> Which NSD server should I run top on, the fs manager? If so the
> >> CPU load
> >> is about 155%. I'm working on perf top but not off to a great
> >> start...
> >>
> >> # perf top
> >> PerfTop: 1095 irqs/sec kernel:61.9% exact: 0.0% [1000Hz
> >> cycles], (all, 28 CPUs)
> >>
> >>
> ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
> >>
> >> Segmentation fault
> >>
> >> -Aaron
> >>
> >> On 3/24/17 1:04 PM, Sven Oehme wrote:
> >> > while this is happening run top and see if there is very high cpu
> >> > utilization at this time on the NSD Server.
> >> >
> >> > if there is , run perf top (you might need to install perf
> >> command) and
> >> > see if the top cpu contender is a spinlock . if so send a
> >> screenshot of
> >> > perf top as i may know what that is and how to fix.
> >> >
> >> > sven
> >> >
> >> >
> >> > On Fri, Mar 24, 2017 at 9:43 AM Aaron Knister
> >> <aaron.s.knister at nasa.gov <mailto:aaron.s.knister at nasa.gov>
> >> > <mailto:aaron.s.knister at nasa.gov
> >> <mailto:aaron.s.knister at nasa.gov>>> wrote:
> >> >
> >> > Since yesterday morning we've noticed some deadlocks on one
> >> of our
> >> > filesystems that seem to be triggered by writing to it. The
> >> waiters on
> >> > the clients look like this:
> >> >
> >> > 0x19450B0 ( 6730) waiting 2063.294589599 seconds,
> >> SyncHandlerThread:
> >> > on ThCond 0x1802585CB10 (0xFFFFC9002585CB10)
> >> (InodeFlushCondVar), reason
> >> > 'waiting for the flush flag to commit metadata'
> >> > 0x7FFFDA65E200 ( 22850) waiting 0.000246257 seconds,
> >> > AllocReduceHelperThread: on ThCond 0x7FFFDAC7FE28
> >> (0x7FFFDAC7FE28)
> >> > (MsgRecordCondvar), reason 'RPC wait' for
> >> allocMsgTypeRelinquishRegion
> >> > on node 10.1.52.33 <c0n3271>
> >> > 0x197EE70 ( 6776) waiting 0.000198354 seconds,
> >> > FileBlockWriteFetchHandlerThread: on ThCond 0x7FFFF00CD598
> >> > (0x7FFFF00CD598) (MsgRecordCondvar), reason 'RPC wait' for
> >> > allocMsgTypeRequestRegion on node 10.1.52.33 <c0n3271>
> >> >
> >> > (10.1.52.33/c0n3271 <http://10.1.52.33/c0n3271>
> >> <http://10.1.52.33/c0n3271> is the fs manager
> >> > for the filesystem in question)
> >> >
> >> > there's a single process running on this node writing to the
> >> filesystem
> >> > in question (well, trying to write, it's been blocked doing
> >> nothing for
> >> > half an hour now). There are ~10 other client nodes in this
> >> situation
> >> > right now. We had many more last night before the problem
> >> seemed to
> >> > disappear in the early hours of the morning and now its back.
> >> >
> >> > Waiters on the fs manager look like this. While the
> >> individual waiter is
> >> > short it's a near constant stream:
> >> >
> >> > 0x7FFF60003540 ( 8269) waiting 0.001151588 seconds, Msg
> >> handler
> >> > allocMsgTypeRequestRegion: on ThMutex 0x1802163A2E0
> >> (0xFFFFC9002163A2E0)
> >> > (AllocManagerMutex)
> >> > 0x7FFF601C8860 ( 20606) waiting 0.001115712 seconds, Msg
> >> handler
> >> > allocMsgTypeRelinquishRegion: on ThMutex 0x1802163A2E0
> >> > (0xFFFFC9002163A2E0) (AllocManagerMutex)
> >> > 0x7FFF91C10080 ( 14723) waiting 0.000959649 seconds, Msg
> >> handler
> >> > allocMsgTypeRequestRegion: on ThMutex 0x1802163A2E0
> >> (0xFFFFC9002163A2E0)
> >> > (AllocManagerMutex)
> >> > 0x7FFFB03C2910 ( 12636) waiting 0.000769611 seconds, Msg
> >> handler
> >> > allocMsgTypeRequestRegion: on ThMutex 0x1802163A2E0
> >> (0xFFFFC9002163A2E0)
> >> > (AllocManagerMutex)
> >> > 0x7FFF8C092850 ( 18215) waiting 0.000682275 seconds, Msg
> >> handler
> >> > allocMsgTypeRelinquishRegion: on ThMutex 0x1802163A2E0
> >> > (0xFFFFC9002163A2E0) (AllocManagerMutex)
> >> > 0x7FFF9423F730 ( 12652) waiting 0.000641915 seconds, Msg
> >> handler
> >> > allocMsgTypeRequestRegion: on ThMutex 0x1802163A2E0
> >> (0xFFFFC9002163A2E0)
> >> > (AllocManagerMutex)
> >> > 0x7FFF9422D770 ( 12625) waiting 0.000494256 seconds, Msg
> >> handler
> >> > allocMsgTypeRequestRegion: on ThMutex 0x1802163A2E0
> >> (0xFFFFC9002163A2E0)
> >> > (AllocManagerMutex)
> >> > 0x7FFF9423E310 ( 12651) waiting 0.000437760 seconds, Msg
> >> handler
> >> > allocMsgTypeRelinquishRegion: on ThMutex 0x1802163A2E0
> >> > (0xFFFFC9002163A2E0) (AllocManagerMutex)
> >> >
> >> > I don't know if this data point is useful but both yesterday
> >> and today
> >> > the metadata NSDs for this filesystem have had a constant
> >> aggregate
> >> > stream of 25MB/s 4kop/s reads during each episode (very low
> >> latency
> >> > though so I don't believe the storage is a bottleneck here).
> >> Writes are
> >> > only a few hundred ops and didn't strike me as odd.
> >> >
> >> > I have a PMR open for this but I'm curious if folks have
> >> seen this in
> >> > the wild and what it might mean.
> >> >
> >> > -Aaron
> >> >
> >> > --
> >> > Aaron Knister
> >> > NASA Center for Climate Simulation (Code 606.2)
> >> > Goddard Space Flight Center
> >> > (301) 286-2776 <tel:(301)%20286-2776> <tel:(301)%20286-2776>
> >> > _______________________________________________
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> >> <http://spectrumscale.org> <http://spectrumscale.org>
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> >> >
> >> >
> >> >
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> >> >
> >>
> >> --
> >> Aaron Knister
> >> NASA Center for Climate Simulation (Code 606.2)
> >> Goddard Space Flight Center
> >> (301) 286-2776 <tel:(301)%20286-2776>
> >> _______________________________________________
> >> gpfsug-discuss mailing list
> >> gpfsug-discuss at spectrumscale.org <http://spectrumscale.org>
> >> http://gpfsug.org/mailman/listinfo/gpfsug-discuss
> >>
> >>
> >>
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> >
> >
> >
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>
> --
> Aaron Knister
> NASA Center for Climate Simulation (Code 606.2)
> Goddard Space Flight Center
> (301) 286-2776
> _______________________________________________
> gpfsug-discuss mailing list
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> http://gpfsug.org/mailman/listinfo/gpfsug-discuss
>
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