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. > >> 6. MDS come back to life after that. >> 7. Ceph loses one directory and as soon as the client tries to access >> it the MDS also suicides. Standing bug: >> http://tracker.ceph.com/issues/9880 >> 8. Lame workaround (moving / renaming bad dir) so client doesn't access it. >> >> -- >> Milosz Tanski >> CTO >> 16 East 34th Street, 15th floor >> New York, NY 10016 >> >> p: 646-253-9055 >> e: milosz@xxxxxxxxx -- Milosz Tanski CTO 16 East 34th Street, 15th floor New York, NY 10016 p: 646-253-9055 e: milosz@xxxxxxxxx -- 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
