Re: Suiciding and corrupted OSDs zero out Ceph cluster IO

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If you had no luck with the cep-post file, you may also find the
uploaded logs @ the following url:
https://files.noc.grnet.gr/aqhzgq6q6furshaxiky3-ikduxv2xcwinlgv3

On 16 September 2016 at 21:45, Kostis Fardelas <dante1234@xxxxxxxxx> wrote:
> Sorry Haomai, I have no idea
>
> On 16 September 2016 at 18:45, Haomai Wang <haomai@xxxxxxxx> wrote:
>> On Fri, Sep 16, 2016 at 7:30 PM, Kostis Fardelas <dante1234@xxxxxxxxx> wrote:
>>> Sure,
>>> ceph-post-file: ebc211d2-5ae1-40ee-b40a-7668a21232e6
>>
>> Oh, sorry, I forget how to access this post... Anyone may give a guide.....
>>
>>>
>>> Contains the ceph logs and crashed OSD logs with default debug level.
>>> The flapping problem starts @2016-09-09 20:57:14.230840 and the OSDs
>>> crash (with suicide and corrupted leveldb logs) @2016-09-10 between
>>> 02:04 - 02:40. You will notice tha when we tried to start them some
>>> hours later, the OSDs kept crashing but with different asserts.
>>>
>>> On 16 September 2016 at 13:34, Haomai Wang <haomai@xxxxxxxx> wrote:
>>>> On Fri, Sep 16, 2016 at 5:11 PM, Kostis Fardelas <dante1234@xxxxxxxxx> wrote:
>>>>> (sent this email to ceph-users too, but there was no feedback due to
>>>>> to its complex issues I guess, so I am sending this in ceph-devel too.
>>>>> Thanks)
>>>>>
>>>>> Hello cephers,
>>>>> last week we survived a 3-day outage on our ceph cluster (Hammer
>>>>> 0.94.7, 162 OSDs, 27 "fat" nodes, 1000s of clients) due to 6 out of
>>>>> 162 OSDs crash in the SAME node. The outage was caused in the
>>>>> following timeline:
>>>>> time 0:  OSDs living in the same node (rd0-19) start heavily flapping
>>>>> (in the logs: failed, wrongly marked me down, RESETSESSION etc). Some
>>>>> more OSDs on other nodes are also flapping but the OSDs of this single
>>>>> node seem to have played the major part in this problem
>>>>>
>>>>> time +6h: rd0-19 OSDs assert. Two of them suicide on OSD::osd_op_tp
>>>>> thread timeout and the other ones assert with EPERM and corrupted
>>>>> leveldb related errors. Something like this:
>>>>>
>>>>> 2016-09-10 02:40:47.155718 7f699b724700  0 filestore(/rados/rd0-19-01)
>>>>>  error (1) Operation not permitted not handled on operation 0x46db2d00
>>>>> (1731767079.0.0, or op 0, counting from 0)
>>>>> 2016-09-10 02:40:47.155731 7f699b724700  0 filestore(/rados/rd0-19-01)
>>>>> unexpected error code
>>>>> 2016-09-10 02:40:47.155732 7f699b724700  0 filestore(/rados/rd0-19-01)
>>>>>  transaction dump:
>>>>> {
>>>>>     "ops": [
>>>>>         {
>>>>>             "op_num": 0,
>>>>>             "op_name": "omap_setkeys",
>>>>>             "collection": "3.b30_head",
>>>>>             "oid": "3\/b30\/\/head",
>>>>>             "attr_lens": {
>>>>>                 "_epoch": 4,
>>>>>                 "_info": 734
>>>>>             }
>>>>>         }
>>>>>     ]
>>>>> }
>>>>>
>>>>>
>>>>> 2016-09-10 02:40:47.155778 7f699671a700 -1 os/FileStore.cc: In
>>>>> function 'unsigned int
>>>>> FileStore::_do_transaction(ObjectStore::Transaction&, uint64_t, int,
>>>>> ThreadPool::TPH
>>>>> andle*)' thread 7f699671a700 time 2016-09-10 02:40:47.153544
>>>>> os/FileStore.cc: 2761: FAILED assert(0 == "unexpected error")
>>>>>
>>>>> This leaves the cluster in a state like below:
>>>>> 2016-09-10 03:04:31.927635 mon.0 62.217.119.14:6789/0 948003 : cluster
>>>>> [INF] osdmap e281474: 162 osds: 156 up, 156 in
>>>>> 2016-09-10 03:04:32.145074 mon.0 62.217.119.14:6789/0 948004 : cluster
>>>>> [INF] pgmap v105867219: 28672 pgs: 1
>>>>> active+recovering+undersized+degraded, 26684 active+clean, 1889
>>>>> active+undersized+degraded, 98 down+peering; 95983 GB data, 179 TB
>>>>> used, 101379 GB / 278 TB avail; 12106 B/s rd, 11 op/s;
>>>>> 2408539/69641962 objects degraded (3.458%); 1/34820981 unfound
>>>>> (0.000%)
>>>>>
>>>>> From this time we have almost no IO propably due to 98 down+peering
>>>>> PGs, 1 unfound object and 1000s of librados clients stuck.
>>>>> As of now, we have not managed to pinpoint what caused the crashes (no
>>>>> disk errors, no network errors, no general hardware errors, nothing in
>>>>> dmesg) but things are still under investigation. Finally we managed to
>>>>> bring up enough crashed OSDs for IO to continue (using gdb, leveldb
>>>>> repairs, ceph-objectstore-tool), but our main questions exists:
>>>>>
>>>>> A. the 6 OSDs were on the same node. What is so special about
>>>>> suiciding + EPERMs that leave the cluster with down+peering and zero
>>>>> IO? Is this a normal behaviour after a crash like this? Notice that
>>>>> the cluster has marked the crashed OSDs down+out, so it seems that the
>>>>> cluster somehow "fenced" these OSDs but in a manner that leaves the
>>>>> cluster unusable. Our crushmap is the default one with the host as a
>>>>> failure domain
>>>>> B. would replication=3 help? Would we need replication=3 and min=2 to
>>>>> avoid such a problem in the future? Right now we are on size=2 &
>>>>> min_size=1
>>>>> C. would an increase in suicide timeouts help for future incidents like this?
>>>>> D. are there any known related bugs on 0.94.7? Haven't found anything so far...
>>>>
>>>> Could you please provide with ceph.log and the down osd logs at that
>>>> time? I don't have clue in your description so far.
>>>>
>>>>>
>>>>> Regards,
>>>>> Kostis
>>>>> --
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