On Mon, Mar 12, 2018 at 7:53 AM, Дробышевский, Владимир <vlad@xxxxxxxxxx> wrote:
>
> I was following this conversation on tracker and got the same question. I've
> got a situation with slow requests and had no any idea on how to find the
> reason. Finally I found it but only because I knew I've upgraded Mellanox
> drivers on one host, and just decided to check IB config (and the root was
> there: adapter switched into the datagram mode). But if it wouldn't be the
> reason I would really lost.
>
> 12 мар. 2018 г. 9:39 пользователь "Alex Gorbachev" <ag@xxxxxxxxxxxxxxxxxxx>
> написал:
>
>> On Mon, Mar 5, 2018 at 11:20 PM, Brad Hubbard <bhubbard@xxxxxxxxxx> wrote:
>> > On Fri, Mar 2, 2018 at 3:54 PM, Alex Gorbachev <ag@xxxxxxxxxxxxxxxxxxx>
>> > wrote:
>> >> On Thu, Mar 1, 2018 at 10:57 PM, David Turner <drakonstein@xxxxxxxxx>
>> >> wrote:
>> >>> Blocked requests and slow requests are synonyms in ceph. They are 2
>> >>> names
>> >>> for the exact same thing.
>> >>>
>> >>>
>> >>> On Thu, Mar 1, 2018, 10:21 PM Alex Gorbachev <ag@xxxxxxxxxxxxxxxxxxx>
>> >>> wrote:
>> >>>>
>> >>>> On Thu, Mar 1, 2018 at 2:47 PM, David Turner <drakonstein@xxxxxxxxx>
>> >>>> wrote:
>> >>>> > `ceph health detail` should show you more information about the
>> >>>> > slow
>> >>>> > requests. If the output is too much stuff, you can grep out for
>> >>>> > blocked
>> >>>> > or
>> >>>> > something. It should tell you which OSDs are involved, how long
>> >>>> > they've
>> >>>> > been slow, etc. The default is for them to show '> 32 sec' but
>> >>>> > that may
>> >>>> > very well be much longer and `ceph health detail` will show that.
>> >>>>
>> >>>> Hi David,
>> >>>>
>> >>>> Thank you for the reply. Unfortunately, the health detail only shows
>> >>>> blocked requests. This seems to be related to a compression setting
>> >>>> on the pool, nothing in OSD logs.
>> >>>>
>> >>>> I replied to another compression thread. This makes sense since
>> >>>> compression is new, and in the past all such issues were reflected in
>> >>>> OSD logs and related to either network or OSD hardware.
>> >>>>
>> >>>> Regards,
>> >>>> Alex
>> >>>>
>> >>>> >
>> >>>> > On Thu, Mar 1, 2018 at 2:23 PM Alex Gorbachev
>> >>>> > <ag@xxxxxxxxxxxxxxxxxxx>
>> >>>> > wrote:
>> >>>> >>
>> >>>> >> Is there a switch to turn on the display of specific OSD issues?
>> >>>> >> Or
>> >>>> >> does the below indicate a generic problem, e.g. network and no any
>> >>>> >> specific OSD?
>> >>>> >>
>> >>>> >> 2018-02-28 18:09:36.438300 7f6dead56700 0
>> >>>> >> mon.roc-vm-sc3c234@0(leader).data_health(46) update_stats avail
>> >>>> >> 56%
>> >>>> >> total 15997 MB, used 6154 MB, avail 9008 MB
>> >>>> >> 2018-02-28 18:09:41.477216 7f6dead56700 0 log_channel(cluster)
>> >>>> >> log
>> >>>> >> [WRN] : Health check failed: 73 slow requests are blocked > 32 sec
>> >>>> >> (REQUEST_SLOW)
>> >>>> >> 2018-02-28 18:09:47.552669 7f6dead56700 0 log_channel(cluster)
>> >>>> >> log
>> >>>> >> [WRN] : Health check update: 74 slow requests are blocked > 32 sec
>> >>>> >> (REQUEST_SLOW)
>> >>>> >> 2018-02-28 18:09:53.794882 7f6de8551700 0
>> >>>> >> mon.roc-vm-sc3c234@0(leader) e1 handle_command
>> >>>> >> mon_command({"prefix":
>> >>>> >> "status", "format": "json"} v 0) v1
>> >>>> >>
>> >>>> >> --
>> >>
>> >> I was wrong where the pool compression does not matter, even
>> >> uncompressed pool also generates these slow messages.
>> >>
>> >> Question is why no subsequent message relating to specific OSDs (like
>> >> in Jewel and prior, like this example from RH:
>> >>
>> >> 2015-08-24 13:18:10.024659 osd.1 127.0.0.1:6812/3032 9 : cluster [WRN]
>> >> 6 slow requests, 6 included below; oldest blocked for > 61.758455 secs
>> >>
>> >> 2016-07-25 03:44:06.510583 osd.50 [WRN] slow request 30.005692 seconds
>> >> old, received at {date-time}: osd_op(client.4240.0:8
>> >> benchmark_data_ceph-1_39426_object7 [write 0~4194304] 0.69848840) v4
>> >> currently waiting for subops from [610]
>> >>
>> >> In comparison, my Luminous cluster only shows the general slow/blocked
>> >> message:
>> >>
>> >> 2018-03-01 21:52:54.237270 7f7e419e3700 0 log_channel(cluster) log
>> >> [WRN] : Health check failed: 116 slow requests are blocked > 32 sec
>> >> (REQUEST_SLOW)
>> >> 2018-03-01 21:53:00.282721 7f7e419e3700 0 log_channel(cluster) log
>> >> [WRN] : Health check update: 66 slow requests are blocked > 32 sec
>> >> (REQUEST_SLOW)
>> >> 2018-03-01 21:53:08.534244 7f7e419e3700 0 log_channel(cluster) log
>> >> [WRN] : Health check update: 5 slow requests are blocked > 32 sec
>> >> (REQUEST_SLOW)
>> >> 2018-03-01 21:53:10.382510 7f7e419e3700 0 log_channel(cluster) log
>> >> [INF] : Health check cleared: REQUEST_SLOW (was: 5 slow requests are
>> >> blocked > 32 sec)
>> >> 2018-03-01 21:53:10.382546 7f7e419e3700 0 log_channel(cluster) log
>> >> [INF] : Cluster is now healthy
>> >>
>> >> So where are the details?
>> >
>> > Working on this, thanks.
>> >
>> > See https://tracker.ceph.com/issues/23236
>>
>> As in the tracker, but I think it would be useful to others:
>>
>> If something like below comes up, how do you troubleshoot the cause of
>> past events, especially if this is specific to just a handful of 1000s
>> of OSDs on many hosts?
>>
>> 2018-03-11 22:00:00.000132 mon.roc-vm-sc3c234 [INF] overall HEALTH_OK
>> 2018-03-11 22:44:46.173825 mon.roc-vm-sc3c234 [WRN] Health check
>> failed: 12 slow requests are blocked > 32 sec (REQUEST_SLOW)
>> 2018-03-11 22:44:52.245738 mon.roc-vm-sc3c234 [WRN] Health check
>> update: 9 slow requests are blocked > 32 sec (REQUEST_SLOW)
>> 2018-03-11 22:44:57.925686 mon.roc-vm-sc3c234 [WRN] Health check
>> update: 10 slow requests are blocked > 32 sec (REQUEST_SLOW)
>> 2018-03-11 22:45:02.926031 mon.roc-vm-sc3c234 [WRN] Health check
>> update: 14 slow requests are blocked > 32 sec (REQUEST_SLOW)
>> 2018-03-11 22:45:06.413741 mon.roc-vm-sc3c234 [INF] Health check
>> cleared: REQUEST_SLOW (was: 14 slow requests are blocked > 32 sec)
>> 2018-03-11 22:45:06.413814 mon.roc-vm-sc3c234 [INF] Cluster is now healthy
>> 2018-03-11 23:00:00.000136 mon.roc-vm-sc3c234 [INF] overall HEALTH_OK
>>
>> Thank you,
>> Alex
I am in this situation now, just seeing the slow requests here and
there, no hint or clue as to which OSD this is on. OSD logs do not
show anything indicative of a problem. Network is fine, hosts are
fine, how to troubleshoot?
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