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. > >> >>> >>>> >>>> ceph version 0.94.3 (95cefea9fd9ab740263bf8bb4796fd864d9afe2b) >>>> 1: (ceph::__ceph_assert_fail(char const*, char const*, int, char >>>> const*)+0x8b) [0x94cc1b] >>>> 2: /usr/bin/ceph-mds() [0x7c7df1] >>>> 3: (MDSIOContextBase::complete(int)+0x81) [0x7c83b1] >>>> 4: (Finisher::finisher_thread_entry()+0x1a0) [0x87f490] >>>> 5: (()+0x8182) [0x7fd4fd031182] >>>> 6: (clone()+0x6d) [0x7fd4fb7a047d] >>>> NOTE: a copy of the executable, or `objdump -rdS <executable>` is >>>> needed to interpret this. >> >> -- >> 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 -- 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
