On Mon, Oct 19, 2015 at 8:31 AM, Milosz Tanski <milosz@xxxxxxxxx> wrote: > On Wed, Oct 14, 2015 at 12:46 AM, Gregory Farnum <gfarnum@xxxxxxxxxx> wrote: >> On Sun, Oct 11, 2015 at 7:36 PM, Milosz Tanski <milosz@xxxxxxxxx> wrote: >>> On Sun, Oct 11, 2015 at 6:44 PM, Milosz Tanski <milosz@xxxxxxxxx> wrote: >>>> On Sun, Oct 11, 2015 at 6:01 PM, Milosz Tanski <milosz@xxxxxxxxx> wrote: >>>>> On Sun, Oct 11, 2015 at 5:33 PM, Milosz Tanski <milosz@xxxxxxxxx> wrote: >>>>>> On Sun, Oct 11, 2015 at 5:24 PM, Milosz Tanski <milosz@xxxxxxxxx> wrote: >>>>>>> On Sun, Oct 11, 2015 at 1:16 PM, Gregory Farnum <gfarnum@xxxxxxxxxx> wrote: >>>>>>>> On Sun, Oct 11, 2015 at 10:09 AM, Milosz Tanski <milosz@xxxxxxxxx> wrote: >>>>>>>>> About an hour ago my MDSs (primary and follower) started ping-pong >>>>>>>>> crashing with this message. I've spent about 30 minutes looking into >>>>>>>>> it but nothing yet. >>>>>>>>> >>>>>>>>> This is from a 0.94.3 MDS >>>>>>>>> >>>>>>>> >>>>>>>>> 0> 2015-10-11 17:01:23.596008 7fd4f52ad700 -1 mds/SessionMap.cc: >>>>>>>>> In function 'virtual void C_IO_SM_Save::finish(int)' thread >>>>>>>>> 7fd4f52ad700 time 2015-10-11 17:01:23.594089 >>>>>>>>> mds/SessionMap.cc: 120: FAILED assert(r == 0) >>>>>>>> >>>>>>>> These "r == 0" asserts pretty much always mean that the MDS did did a >>>>>>>> read or write to RADOS (the OSDs) and got an error of some kind back. >>>>>>>> (Or in the case of the OSDs, access to the local filesystem returned >>>>>>>> an error, etc.) I don't think these writes include any safety checks >>>>>>>> which would let the MDS break it which means that probably the OSD is >>>>>>>> actually returning an error — odd, but not impossible. >>>>>>>> >>>>>>>> Notice that the assert happened in thread 7fd4f52ad700, and look for >>>>>>>> the stuff in that thread. You should be able to find an OSD op reply >>>>>>>> (on the SessionMap object) coming in and reporting an error code. >>>>>>>> -Greg >>>>>>> >>>>>>> I only two error ops in that whole MDS session. Neither one happened >>>>>>> on the same thread (7f5ab6000700 in this file). But it looks like the >>>>>>> only session map is the -90 "Message too long" one. >>>>>>> >>>>>>> mtanski@tiny:~$ cat single_crash.log | grep 'osd_op_reply' | grep -v >>>>>>> 'ondisk = 0' >>>>>>> -3946> 2015-10-11 20:51:11.013965 7f5ab20f2700 1 -- >>>>>>> 10.0.5.31:6802/27121 <== osd.25 10.0.5.57:6804/32341 6163 ==== >>>>>>> osd_op_reply(46349 mds0_sessionmap [writefull 0~95168363] v0'0 uv0 >>>>>>> ondisk = -90 ((90) Message too long)) v6 ==== 182+0+0 (2955408122 0 0) >>>>>>> 0x3a55d340 con 0x3d5a3c0 >>>>>>> -705> 2015-10-11 20:51:11.374132 7f5ab22f4700 1 -- >>>>>>> 10.0.5.31:6802/27121 <== osd.28 10.0.5.50:6801/1787 5297 ==== >>>>>>> osd_op_reply(48004 300.0000e274 [delete] v0'0 uv1349638 ondisk = -2 >>>>>>> ((2) No such file or directory)) v6 ==== 179+0+0 (1182549251 0 0) >>>>>>> 0x66c5c80 con 0x3d5a7e0 >>>>>>> >>>>>>> Any idea what this could be Greg? >>>>>> >>>>>> To follow this up I found this ticket from 9 months ago: >>>>>> http://tracker.ceph.com/issues/10449 In there Yan says: >>>>>> >>>>>> "it's a kernel bug. hang request prevents mds from trimming >>>>>> completed_requests in sessionmap. there is nothing to do with mds. >>>>>> (maybe we should add some code to MDS to show warning when this bug >>>>>> happens)" >>>>>> >>>>>> When I was debugging this I saw an OSD (not cephfs client) operation >>>>>> stuck for a long time along with the MDS error: >>>>>> >>>>>> HEALTH_WARN 1 requests are blocked > 32 sec; 1 osds have slow >>>>>> requests; mds cluster is degraded; mds0: Behind on trimming (709/30) >>>>>> 1 ops are blocked > 16777.2 sec >>>>>> 1 ops are blocked > 16777.2 sec on osd.28 >>>>>> >>>>>> I did eventually bounce the OSD in question and it hasn't become stuck >>>>>> since, but the MDS is still eating it every time with the "Message too >>>>>> long" error on the session map. >>>>>> >>>>>> I'm not quite sure where to go from here. >>>>> >>>>> First time I had a chance to use the new recover tools. I was able to >>>>> reply the journal, reset it and then reset the sessionmap. MDS >>>>> returned back to life and so far everything looks good. Yay. >>>>> >>>>> Triggering this a bug/issue is a pretty interesting set of steps. >>>> >>>> Spoke too soon, a missing dir is now causing MDS to restart it self. >>>> >>>> -6> 2015-10-11 22:40:47.300169 7f580c7b9700 5 -- op tracker -- >>>> seq: 4, time: 2015-10-11 22:40:47.300168, event: finishing request, >>>> op: client_request(client.3597476:21480382 rmdir #100015e0be2/58 >>>> 2015-10-11 21:34:49.224905 RETRY=36) >>>> -5> 2015-10-11 22:40:47.300208 7f580c7b9700 5 -- op tracker -- >>>> seq: 4, time: 2015-10-11 22:40:47.300208, event: cleaned up request, >>>> op: client_request(client.3597476:21480382 rmdir #100015e0be2/58 >>>> 2015-10-11 21:34:49.224905 RETRY=36) >>>> -4> 2015-10-11 22:40:47.300231 7f580c7b9700 5 -- op tracker -- >>>> seq: 4, time: 2015-10-11 22:40:47.300231, event: done, op: >>>> client_request(client.3597476:21480382 rmdir #100015e0be2/58 >>>> 2015-10-11 21:34:49.224905 RETRY=36) >>>> -3> 2015-10-11 22:40:47.300284 7f580e0bd700 0 >>>> mds.0.cache.dir(100048df076) _fetched missing object for [dir >>>> 100048df076 /petabucket/beta/6d/f6/ [2,head] auth v=0 cv=0/0 ap=1+0+0 >>>> state=1073741952 f() n() hs=0+0,ss=0+0 | waiter=1 authpin=1 0x6debcf8] >>>> -2> 2015-10-11 22:40:47.300313 7f580e0bd700 -1 >>>> log_channel(cluster) log [ERR] : dir 100048df076 object missing on >>>> disk; some files may be lost >>>> -1> 2015-10-11 22:40:47.300549 7f580c7b9700 5 -- op tracker -- >>>> seq: 6, time: 2015-10-11 22:40:47.300549, event: acquired locks, op: >>>> client_request(client.3710941:1805 mkdir >>>> #100048df076/1dd4c66b916cf55f19beafc0574ac2dd923bc7efcc5b7757198f323e04d0.dl >>>> 2015-10-11 22:36:32.489705 RETRY=33) >>>> 0> 2015-10-11 22:40:47.303770 7f580c7b9700 -1 mds/CDir.cc: In >>>> function 'fnode_t* CDir::project_fnode()' thread 7f580c7b9700 time >>>> 2015-10-11 22:40:47.300581 >>>> mds/CDir.cc: 1267: FAILED assert(get_version() != 0) >>>> >>>> ceph version 0.94.3 (95cefea9fd9ab740263bf8bb4796fd864d9afe2b) >>>> 1: (ceph::__ceph_assert_fail(char const*, char const*, int, char >>>> const*)+0x8b) [0x94cc1b] >>>> 2: (CDir::project_fnode()+0x2da) [0x75da1a] >>> >>> Worked around this as well. Stopped the client that was trying to >>> access this dir (or delete it, not sure) and move it somewhere else >>> (because I can't delete it). >>> >>> A series of steps that happened today (not sure if all are related) in >>> case the postmortem is interesting to anybody following at home. >>> >>> 1. One (of 5) monitors somehow gets OOM killed after eating up 10gigs of ram. >>> 2. An OSD blocks on an IO request >>> 3. This is when the MSD starts growing it's SessionMap to a place >>> where eventually it gets to big. This is related to bug: >>> http://tracker.ceph.com/issues/10449 (not the client bug, but the too >>> large Session) >>> 4. MDS suicides and then two MDS machines start ping ponging in >>> recovery but always fail to save SessionMap. >>> 5. I stop the MDS, recover the journal and reset the session map. >> >> Exactly what did you do in this step? I have a suspicion you didn't >> recover and flush out the journal all the way, and that's what caused >> your directory to go bad. >> -Greg > > I followed the directions from the hammer recovery page on cephfs. The > backup steps, recovery, truncation and the session clear in order. John, I know you've got https://github.com/ceph/ceph-qa-suite/pull/647. I think that's supposed to be for this, but I'm not sure if you spotted any issues with it or if we need to do some more diagnosing? -Greg -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
