Hi Frank, Can you try `perf top` to find out what the ceph-mds process is doing with that CPU time? Also Mark's profiler is super useful to find those busy loops: https://github.com/markhpc/uwpmp Cheers, Dan -- Dan van der Ster CTO @ CLYSO Try our Ceph Analyzer -- https://analyzer.clyso.com/ https://clyso.com | dan.vanderster@xxxxxxxxx On Fri, Jan 10, 2025 at 2:06 PM Frank Schilder <frans@xxxxxx> wrote: > > Hi Bailey, > > I already set that value very high: > > # ceph config get mds.ceph-12 mds_beacon_grace > 600000.000000 > > To no avail. The 15s heartbeat timeout comes from somewhere else. What I observe is that the MDS loads the stray buckets (up to 87Mio DNS/INOS) and as soon as that happened it seems to start doing something (RAM usage grows without the DNS/INOS changing any more). However, shortly after the timeout happens, everything comes to a standstill. I think the MONs keep the MDS assigned but its no longer part of the file system or the actual MDS worker thread terminates with this timeout. > > Its reported as up and active, but this report seems just outdated as all status queries to the MDS just hang. My suspicion is that the MONs don't kick it out yet (no fail-over triggered), but the rank is actually not really active. The report just doesn't update. > > I'm stuck here and am out of ideas what to do about it. Increasing the thread timeout would probably help, but I can't find a config option for that. > > I'm afraid I need to take a break. I will be looking at my e-mail in about 4h again. Would be great if there are some further ideas for how to proceed. > > Thanks so far and best regards, > ================= > Frank Schilder > AIT Risø Campus > Bygning 109, rum S14 > > ________________________________________ > From: Bailey Allison <ballison@xxxxxxxxxxxx> > Sent: Friday, January 10, 2025 10:23 PM > To: Frank Schilder; ceph-users@xxxxxxx > Subject: Re: Re: Help needed, ceph fs down due to large stray dir > > Hi Frank, > > The value for that is mds_beacon_grace. Default is 15 but you can jack > it up. Apply it to the monitor or global to take effect. > > Just to clarify too, does the MDS daemon come into up:active ? If it > does, are you able to also access that portion of the filesystem in that > time? > > If you can access the filesystem, try running a stat on that portion > with something like 'find . -ls' in a directory and see if the strays > decrease. > > Regards, > > Bailey Allison > Service Team Lead > 45Drives, Ltd. > 866-594-7199 x868 > > On 1/10/25 17:18, Frank Schilder wrote: > > Hi Bailey, > > > > thanks for your response. The MDS was actually unresponsive and I had to restart it (ceph tell and ceph daemon commands were hanging, except for "help"). Its currently in clientreplay and loading all the stuff again. I'm really worried that this here is the rescue killer: > > > > heartbeat_map is_healthy 'MDSRank' had timed out after 15.000000954s > > > > Do you have any idea how to deal with this timeout? Somewhere in he process the MDS seems to become unresponsive for too long and seems to become unresponsive after that. > > > > I have 4T swap now and the MDS comes up to the point where it actually reports back a number for the stray items. However, some time after it becomes unresponsive and the heartbeat messages start showing up. I don't know how to get past this point. > > > > Best regards, > > ================= > > Frank Schilder > > AIT Risø Campus > > Bygning 109, rum S14 > > > > ________________________________________ > > From: Bailey Allison <ballison@xxxxxxxxxxxx> > > Sent: Friday, January 10, 2025 10:05 PM > > To: ceph-users@xxxxxxx; Frank Schilder > > Subject: Re: Re: Help needed, ceph fs down due to large stray dir > > > > Frank, > > > > You mentioned previously a large number of strays on the mds rank. Are > > you able to check the rank again to see how many strays there are again? > > We've previously had a similar issue, and once the MDS came back up we > > had to stat the filesystem to decrease the number of strays, and which > > doing so everything returned to normal. > > > > ceph tell mds.X perf dump | jq .mds_cache > > > > Bailey Allison > > Service Team Lead > > 45Drives, Ltd. > > 866-594-7199 x868 > > > > On 1/10/25 16:42, Frank Schilder wrote: > >> Hi all, > >> > >> I got the MDS up. however, after quite some time its sitting with almost no CPU load: > >> > >> top - 21:40:02 up 2:49, 1 user, load average: 0.00, 0.02, 0.34 > >> Tasks: 606 total, 1 running, 247 sleeping, 0 stopped, 0 zombie > >> %Cpu(s): 0.0 us, 0.1 sy, 0.0 ni, 99.9 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st > >> GiB Mem : 503.7 total, 12.3 free, 490.3 used, 1.1 buff/cache > >> GiB Swap: 3577.0 total, 3367.0 free, 210.0 used. 2.9 avail Mem > >> > >> PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND > >> 59495 ceph 20 0 685.8g 477.9g 0.0g S 1.0 94.9 53:47.57 ceph-mds > >> > >> I'm not sure if its doing anything at all. Only messages like these keep showing up in the log: > >> > >> 2025-01-10T21:38:08.459+0100 7f87ccd5f700 1 heartbeat_map is_healthy 'MDSRank' had timed out after 15.000000954s > >> 2025-01-10T21:38:08.459+0100 7f87ccd5f700 0 mds.beacon.ceph-12 Skipping beacon heartbeat to monitors (last acked 3019.23s ago); MDS internal heartbeat is not healthy! > >> > >> The MDS cluster looks healthy from this output: > >> > >> # ceph fs status > >> con-fs2 - 1554 clients > >> ======= > >> RANK STATE MDS ACTIVITY DNS INOS DIRS CAPS > >> 0 active ceph-15 Reqs: 0 /s 255k 248k 5434 1678 > >> 1 active ceph-14 Reqs: 2 /s 402k 396k 26.7k 144k > >> 2 active ceph-12 Reqs: 0 /s 86.9M 86.9M 46.2k 3909 > >> 3 active ceph-08 Reqs: 0 /s 637k 630k 2663 7457 > >> 4 active ceph-11 Reqs: 0 /s 1496k 1492k 113k 103k > >> 5 active ceph-16 Reqs: 2 /s 775k 769k 65.3k 12.9k > >> 6 active ceph-24 Reqs: 0 /s 130k 113k 7294 8670 > >> 7 active ceph-13 Reqs: 65 /s 3619k 3609k 469k 47.2k > >> POOL TYPE USED AVAIL > >> con-fs2-meta1 metadata 4078G 7269G > >> con-fs2-meta2 data 0 7258G > >> con-fs2-data data 1225T 2476T > >> con-fs2-data-ec-ssd data 794G 22.6T > >> con-fs2-data2 data 5747T 2253T > >> STANDBY MDS > >> ceph-09 > >> ceph-10 > >> ceph-23 > >> ceph-17 > >> MDS version: ceph version 16.2.15 (618f440892089921c3e944a991122ddc44e60516) pacific (stable) > >> > >> Did it mark itself out of the cluster and is waiting for the MON to fail it?? Please help. > >> > >> Best regards, > >> ================= > >> Frank Schilder > >> AIT Risø Campus > >> Bygning 109, rum S14 > >> > >> ________________________________________ > >> From: Frank Schilder <frans@xxxxxx> > >> Sent: Friday, January 10, 2025 8:51 PM > >> To: Spencer Macphee > >> Cc: ceph-users@xxxxxxx > >> Subject: Re: Help needed, ceph fs down due to large stray dir > >> > >> Hi all, > >> > >> I seem to have gotten the MDS up to the point that it reports stats. Does this mean anything: > >> > >> 2025-01-10T20:50:25.256+0100 7f87ccd5f700 1 heartbeat_map is_healthy 'MDSRank' had timed out after 15.000000954s > >> 2025-01-10T20:50:25.256+0100 7f87ccd5f700 0 mds.beacon.ceph-12 Skipping beacon heartbeat to monitors (last acked 156.027s ago); MDS internal heartbeat is not healthy! > >> > >> I hope it doesn't get failed by some king of timeout now. > >> > >> Best regards, > >> ================= > >> Frank Schilder > >> AIT Risø Campus > >> Bygning 109, rum S14 > >> > >> ________________________________________ > >> From: Spencer Macphee <spencerofsydney@xxxxxxxxx> > >> Sent: Friday, January 10, 2025 7:16 PM > >> To: Frank Schilder > >> Cc: ceph-users@xxxxxxx > >> Subject: Re: Help needed, ceph fs down due to large stray dir > >> > >> I had a similar issue some months ago that ended up using around 300 gigabytes of RAM for a similar number of strays. > >> > >> You can get an idea of the strays kicking around by checking the omapkeys of the stray objects in the cephfs metadata pool. Strays are tracked in objects: 600.00000000, 601.00000000, 602.00000000, etc... etc... That would also give you an indication if it's progressing at each restart. > >> > >> On Fri, Jan 10, 2025 at 1:30 PM Frank Schilder <frans@xxxxxx<mailto:frans@xxxxxx>> wrote: > >> Hi all, > >> > >> we seem to have a serious issue with our file system, ceph version is pacific latest. After a large cleanup operation we had an MDS rank with 100Mio stray entries (yes, one hundred million). Today we restarted this daemon, which cleans up the stray entries. It seems that this leads to a restart loop due to OOM. The rank becomes active and then starts pulling in DNS and INOS entries until all memory is exhausted. > >> > >> I have no idea if there is at least progress removing the stray items or if it starts from scratch every time. If it needs to pull as many DNS/INOS into cache as there are stray items, we don't have a server at hand with enough RAM. > >> > >> Q1: Is the MDS at least making progress in every restart iteration? > >> Q2: If not, how do we get this rank up again? > >> Q3: If we can't get this rank up soon, can we at least move directories away from this rank by pinning it to another rank? > >> > >> Currently, the rank in question reports .mds_cache.num_strays=0 in perf dump. > >> > >> ================= > >> Frank Schilder > >> AIT Risø Campus > >> Bygning 109, rum S14 > >> _______________________________________________ > >> ceph-users mailing list -- ceph-users@xxxxxxx<mailto:ceph-users@xxxxxxx> > >> To unsubscribe send an email to ceph-users-leave@xxxxxxx<mailto:ceph-users-leave@xxxxxxx> > >> _______________________________________________ > >> ceph-users mailing list -- ceph-users@xxxxxxx > >> To unsubscribe send an email to ceph-users-leave@xxxxxxx > _______________________________________________ > ceph-users mailing list -- ceph-users@xxxxxxx > To unsubscribe send an email to ceph-users-leave@xxxxxxx _______________________________________________ ceph-users mailing list -- ceph-users@xxxxxxx To unsubscribe send an email to ceph-users-leave@xxxxxxx
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