On Fri, Nov 11, 2022 at 3:06 AM Olli Rajala <olli.rajala@xxxxxxxx> wrote: > > Hi Venky, > > I have indeed observed the output of the different sections of perf dump like so: > watch -n 1 ceph tell mds.`hostname` perf dump objecter > watch -n 1 ceph tell mds.`hostname` perf dump mds_cache > ...etc... > > ...but without any proper understanding of what is a normal rate for some number to go up it's really difficult to make anything from that. > > btw - is there some convenient way to capture this kind of temporal output for others to view. Sure, I could just dump once a second to a file or sequential files but is there some tool or convention that is easy to look at and analyze? Not really - you'd have to do it yourself. > > Tnx, > --------------------------- > Olli Rajala - Lead TD > Anima Vitae Ltd. > www.anima.fi > --------------------------- > > > On Thu, Nov 10, 2022 at 8:18 AM Venky Shankar <vshankar@xxxxxxxxxx> wrote: >> >> Hi Olli, >> >> On Mon, Oct 17, 2022 at 1:08 PM Olli Rajala <olli.rajala@xxxxxxxx> wrote: >> > >> > Hi Patrick, >> > >> > With "objecter_ops" did you mean "ceph tell mds.pve-core-1 ops" and/or >> > "ceph tell mds.pve-core-1 objecter_requests"? Both these show very few >> > requests/ops - many times just returning empty lists. I'm pretty sure that >> > this I/O isn't generated by any clients - I've earlier tried to isolate >> > this by shutting down all cephfs clients and this didn't have any >> > noticeable effect. >> > >> > I tried to watch what is going on with that "perf dump" but to be honest >> > all I can see is some numbers going up in the different sections :) >> > ...don't have a clue what to focus on and how to interpret that. >> > >> > Here's a perf dump if you or anyone could make something out of that: >> > https://gist.github.com/olliRJL/43c10173aafd82be22c080a9cd28e673 >> >> You'd need to capture this over a period of time to see what ops might >> be going through and what the mds is doing. >> >> > >> > Tnx! >> > o. >> > >> > --------------------------- >> > Olli Rajala - Lead TD >> > Anima Vitae Ltd. >> > www.anima.fi >> > --------------------------- >> > >> > >> > On Fri, Oct 14, 2022 at 8:32 PM Patrick Donnelly <pdonnell@xxxxxxxxxx> >> > wrote: >> > >> > > Hello Olli, >> > > >> > > On Thu, Oct 13, 2022 at 5:01 AM Olli Rajala <olli.rajala@xxxxxxxx> wrote: >> > > > >> > > > Hi, >> > > > >> > > > I'm seeing constant 25-50MB/s writes to the metadata pool even when all >> > > > clients and the cluster is idling and in clean state. This surely can't >> > > be >> > > > normal? >> > > > >> > > > There's no apparent issues with the performance of the cluster but this >> > > > write rate seems excessive and I don't know where to look for the >> > > culprit. >> > > > >> > > > The setup is Ceph 16.2.9 running in hyperconverged 3 node core cluster >> > > and >> > > > 6 hdd osd nodes. >> > > > >> > > > Here's typical status when pretty much all clients are idling. Most of >> > > that >> > > > write bandwidth and maybe fifth of the write iops is hitting the >> > > > metadata pool. >> > > > >> > > > >> > > --------------------------------------------------------------------------------------------------- >> > > > root@pve-core-1:~# ceph -s >> > > > cluster: >> > > > id: 2088b4b1-8de1-44d4-956e-aa3d3afff77f >> > > > health: HEALTH_OK >> > > > >> > > > services: >> > > > mon: 3 daemons, quorum pve-core-1,pve-core-2,pve-core-3 (age 2w) >> > > > mgr: pve-core-1(active, since 4w), standbys: pve-core-2, pve-core-3 >> > > > mds: 1/1 daemons up, 2 standby >> > > > osd: 48 osds: 48 up (since 5h), 48 in (since 4M) >> > > > >> > > > data: >> > > > volumes: 1/1 healthy >> > > > pools: 10 pools, 625 pgs >> > > > objects: 70.06M objects, 46 TiB >> > > > usage: 95 TiB used, 182 TiB / 278 TiB avail >> > > > pgs: 625 active+clean >> > > > >> > > > io: >> > > > client: 45 KiB/s rd, 38 MiB/s wr, 6 op/s rd, 287 op/s wr >> > > > >> > > --------------------------------------------------------------------------------------------------- >> > > > >> > > > Here's some daemonperf dump: >> > > > >> > > > >> > > --------------------------------------------------------------------------------------------------- >> > > > root@pve-core-1:~# ceph daemonperf mds.`hostname -s` >> > > > >> > > ----------------------------------------mds----------------------------------------- >> > > > --mds_cache--- ------mds_log------ -mds_mem- -------mds_server------- >> > > mds_ >> > > > -----objecter------ purg >> > > > req rlat fwd inos caps exi imi hifc crev cgra ctru cfsa cfa hcc >> > > hccd >> > > > hccr prcr|stry recy recd|subm evts segs repl|ino dn |hcr hcs hsr cre >> > > > cat |sess|actv rd wr rdwr|purg| >> > > > 40 0 0 767k 78k 0 0 0 1 6 1 0 0 5 5 >> > > > 3 7 |1.1k 0 0 | 17 3.7k 134 0 |767k 767k| 40 5 0 0 >> > > > 0 |110 | 4 2 21 0 | 2 >> > > > 57 2 0 767k 78k 0 0 0 3 16 3 0 0 11 11 >> > > > 0 17 |1.1k 0 0 | 45 3.7k 137 0 |767k 767k| 57 8 0 0 >> > > > 0 |110 | 0 2 28 0 | 4 >> > > > 57 4 0 767k 78k 0 0 0 4 34 4 0 0 34 33 >> > > > 2 26 |1.0k 0 0 |134 3.9k 139 0 |767k 767k| 57 13 0 0 >> > > > 0 |110 | 0 2 112 0 | 19 >> > > > 67 3 0 767k 78k 0 0 0 6 32 6 0 0 22 22 >> > > > 0 32 |1.1k 0 0 | 78 3.9k 141 0 |767k 768k| 67 4 0 0 >> > > > 0 |110 | 0 2 56 0 | 2 >> > > > >> > > --------------------------------------------------------------------------------------------------- >> > > > Any ideas where to look at? >> > > >> > > Check the perf dump output of the mds: >> > > >> > > ceph tell mds.<fs_name>:0 perf dump >> > > >> > > over a period of time to identify what's going on. You can also look >> > > at the objecter_ops (another tell command) for the MDS. >> > > >> > > -- >> > > Patrick Donnelly, Ph.D. >> > > He / Him / His >> > > Principal Software Engineer >> > > Red Hat, Inc. >> > > GPG: 19F28A586F808C2402351B93C3301A3E258DD79D >> > > >> > > >> > _______________________________________________ >> > ceph-users mailing list -- ceph-users@xxxxxxx >> > To unsubscribe send an email to ceph-users-leave@xxxxxxx >> > >> >> >> -- >> Cheers, >> Venky >> -- Cheers, Venky _______________________________________________ ceph-users mailing list -- ceph-users@xxxxxxx To unsubscribe send an email to ceph-users-leave@xxxxxxx
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