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
