Hi Aaron- Sorry, lost track of this one. In order to get backtraces out of the core you need the matching executables. Can you make sure the ceph-osd-dbg or ceph-debuginfo package is installed on the machine (depending on if it's deb or rpm) and then gdb ceph-osd corefile and 'thr app all bt'? Thanks! sage On Thu, 4 May 2017, Aaron Ten Clay wrote: > Were the backtraces we obtained not useful? Is there anything else we > can try to get the OSDs up again? > > On Wed, Apr 19, 2017 at 4:18 PM, Aaron Ten Clay <aarontc@xxxxxxxxxxx> wrote: > > I'm new to doing this all via systemd and systemd-coredump, but I appear to > > have gotten cores from two OSD processes. When xzipped they are < 2MIB each, > > but I threw them on my webserver to avoid polluting the mailing list. This > > seems oddly small, so if I've botched the process somehow let me know :) > > > > https://aarontc.com/ceph/dumps/core.ceph-osd.150.082e9ca887c34cfbab183366a214a84c.6742.1492634493000000000000.xz > > https://aarontc.com/ceph/dumps/core.ceph-osd.150.082e9ca887c34cfbab183366a214a84c.7202.1492634508000000000000.xz > > > > And for reference: > > root@osd001:/var/lib/systemd/coredump# ceph -v > > ceph version 11.2.0 (f223e27eeb35991352ebc1f67423d4ebc252adb7) > > > > > > I am also investigating sysdig as recommended. > > > > Thanks! > > -Aaron > > > > > > On Mon, Apr 17, 2017 at 8:15 AM, Sage Weil <sage@xxxxxxxxxxxx> wrote: > >> > >> On Sat, 15 Apr 2017, Aaron Ten Clay wrote: > >> > Hi all, > >> > > >> > Our cluster is experiencing a very odd issue and I'm hoping for some > >> > guidance on troubleshooting steps and/or suggestions to mitigate the > >> > issue. > >> > tl;dr: Individual ceph-osd processes try to allocate > 90GiB of RAM and > >> > are > >> > eventually nuked by oom_killer. > >> > >> My guess is that there there is a bug in a decoding path and it's > >> trying to allocate some huge amount of memory. Can you try setting a > >> memory ulimit to something like 40gb and then enabling core dumps so you > >> can get a core? Something like > >> > >> ulimit -c unlimited > >> ulimit -m 20000000 > >> > >> or whatever the corresponding systemd unit file options are... > >> > >> Once we have a core file it will hopefully be clear who is > >> doing the bad allocation... > >> > >> sage > >> > >> > >> > >> > > >> > I'll try to explain the situation in detail: > >> > > >> > We have 24-4TB bluestore HDD OSDs, and 4-600GB SSD OSDs. The SSD OSDs > >> > are in > >> > a different CRUSH "root", used as a cache tier for the main storage > >> > pools, > >> > which are erasure coded and used for cephfs. The OSDs are spread across > >> > two > >> > identical machines with 128GiB of RAM each, and there are three monitor > >> > nodes on different hardware. > >> > > >> > Several times we've encountered crippling bugs with previous Ceph > >> > releases > >> > when we were on RC or betas, or using non-recommended configurations, so > >> > in > >> > January we abandoned all previous Ceph usage, deployed LTS Ubuntu 16.04, > >> > and > >> > went with stable Kraken 11.2.0 with the configuration mentioned above. > >> > Everything was fine until the end of March, when one day we find all but > >> > a > >> > couple of OSDs are "down" inexplicably. Investigation reveals oom_killer > >> > came along and nuked almost all the ceph-osd processes. > >> > > >> > We've gone through a bunch of iterations of restarting the OSDs, trying > >> > to > >> > bring them up one at a time gradually, all at once, various > >> > configuration > >> > settings to reduce cache size as suggested in this ticket: > >> > http://tracker.ceph.com/issues/18924... > >> > > >> > I don't know if that ticket really pertains to our situation or not, I > >> > have > >> > no experience with memory allocation debugging. I'd be willing to try if > >> > someone can point me to a guide or walk me through the process. > >> > > >> > I've even tried, just to see if the situation was transitory, adding > >> > over > >> > 300GiB of swap to both OSD machines. The OSD procs managed to allocate, > >> > in a > >> > matter of 5-10 minutes, more than 300GiB of RAM pressure and became > >> > oom_killer victims once again. > >> > > >> > No software or hardware changes took place around the time this problem > >> > started, and no significant data changes occurred either. We added about > >> > 40GiB of ~1GiB files a week or so before the problem started and that's > >> > the > >> > last time data was written. > >> > > >> > I can only assume we've found another crippling bug of some kind, this > >> > level > >> > of memory usage is entirely unprecedented. What can we do? > >> > > >> > Thanks in advance for any suggestions. > >> > -Aaron > >> > > >> > > > > > > > > > > > -- > > Aaron Ten Clay > > https://aarontc.com > > > > -- > Aaron Ten Clay > https://aarontc.com > > -- 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
