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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