Re: osd_memory_target exceeding on Luminous OSD BlueStore

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Well, Dan seems to be right :

_tune_cache_size
        target: 4294967296
          heap: 6514409472
      unmapped: 2267537408
        mapped: 4246872064
old cache_size: 2845396873
new cache size: 2845397085


So we have 6GB in heap, but "only" 4GB mapped.

But "ceph tell osd.* heap release" should had release that ?


Thanks,

Olivier


Le lundi 08 avril 2019 à 16:09 -0500, Mark Nelson a écrit :
> One of the difficulties with the osd_memory_target work is that we
> can't 
> tune based on the RSS memory usage of the process. Ultimately it's up
> to 
> the kernel to decide to reclaim memory and especially with
> transparent 
> huge pages it's tough to judge what the kernel is going to do even
> if 
> memory has been unmapped by the process.  Instead the autotuner looks
> at 
> how much memory has been mapped and tries to balance the caches based
> on 
> that.
> 
> 
> In addition to Dan's advice, you might also want to enable debug 
> bluestore at level 5 and look for lines containing "target:" and 
> "cache_size:".  These will tell you the current target, the mapped 
> memory, unmapped memory, heap size, previous aggregate cache size,
> and 
> new aggregate cache size.  The other line will give you a break down
> of 
> how much memory was assigned to each of the bluestore caches and how 
> much each case is using.  If there is a memory leak, the autotuner
> can 
> only do so much.  At some point it will reduce the caches to fit
> within 
> cache_min and leave it there.
> 
> 
> Mark
> 
> 
> On 4/8/19 5:18 AM, Dan van der Ster wrote:
> > Which OS are you using?
> > With CentOS we find that the heap is not always automatically
> > released. (You can check the heap freelist with `ceph tell osd.0
> > heap
> > stats`).
> > As a workaround we run this hourly:
> > 
> > ceph tell mon.* heap release
> > ceph tell osd.* heap release
> > ceph tell mds.* heap release
> > 
> > -- Dan
> > 
> > On Sat, Apr 6, 2019 at 1:30 PM Olivier Bonvalet <
> > ceph.list@xxxxxxxxx> wrote:
> > > Hi,
> > > 
> > > on a Luminous 12.2.11 deploiement, my bluestore OSD exceed the
> > > osd_memory_target :
> > > 
> > > daevel-ob@ssdr712h:~$ ps auxw | grep ceph-osd
> > > ceph        3646 17.1 12.0 6828916 5893136 ?     Ssl  mars29
> > > 1903:42 /usr/bin/ceph-osd -f --cluster ceph --id 143 --setuser
> > > ceph --setgroup ceph
> > > ceph        3991 12.9 11.2 6342812 5485356 ?     Ssl  mars29
> > > 1443:41 /usr/bin/ceph-osd -f --cluster ceph --id 144 --setuser
> > > ceph --setgroup ceph
> > > ceph        4361 16.9 11.8 6718432 5783584 ?     Ssl  mars29
> > > 1889:41 /usr/bin/ceph-osd -f --cluster ceph --id 145 --setuser
> > > ceph --setgroup ceph
> > > ceph        4731 19.7 12.2 6949584 5982040 ?     Ssl  mars29
> > > 2198:47 /usr/bin/ceph-osd -f --cluster ceph --id 146 --setuser
> > > ceph --setgroup ceph
> > > ceph        5073 16.7 11.6 6639568 5701368 ?     Ssl  mars29
> > > 1866:05 /usr/bin/ceph-osd -f --cluster ceph --id 147 --setuser
> > > ceph --setgroup ceph
> > > ceph        5417 14.6 11.2 6386764 5519944 ?     Ssl  mars29
> > > 1634:30 /usr/bin/ceph-osd -f --cluster ceph --id 148 --setuser
> > > ceph --setgroup ceph
> > > ceph        5760 16.9 12.0 6806448 5879624 ?     Ssl  mars29
> > > 1882:42 /usr/bin/ceph-osd -f --cluster ceph --id 149 --setuser
> > > ceph --setgroup ceph
> > > ceph        6105 16.0 11.6 6576336 5694556 ?     Ssl  mars29
> > > 1782:52 /usr/bin/ceph-osd -f --cluster ceph --id 150 --setuser
> > > ceph --setgroup ceph
> > > 
> > > daevel-ob@ssdr712h:~$ free -m
> > >                total        used        free      shared  buff/ca
> > > che   available
> > > Mem:          47771       45210        1643          17         9
> > > 17       43556
> > > Swap:             0           0           0
> > > 
> > > # ceph daemon osd.147 config show | grep memory_target
> > >      "osd_memory_target": "4294967296",
> > > 
> > > 
> > > And there is no recovery / backfilling, the cluster is fine :
> > > 
> > >     $ ceph status
> > >       cluster:
> > >         id:     de035250-323d-4cf6-8c4b-cf0faf6296b1
> > >         health: HEALTH_OK
> > > 
> > >       services:
> > >         mon: 5 daemons, quorum tolriq,tsyne,olkas,lorunde,amphel
> > >         mgr: tsyne(active), standbys: olkas, tolriq, lorunde,
> > > amphel
> > >         osd: 120 osds: 116 up, 116 in
> > > 
> > >       data:
> > >         pools:   20 pools, 12736 pgs
> > >         objects: 15.29M objects, 31.1TiB
> > >         usage:   101TiB used, 75.3TiB / 177TiB avail
> > >         pgs:     12732 active+clean
> > >                  4     active+clean+scrubbing+deep
> > > 
> > >       io:
> > >         client:   72.3MiB/s rd, 26.8MiB/s wr, 2.30kop/s rd,
> > > 1.29kop/s wr
> > > 
> > > 
> > >     On an other host, in the same pool, I see also high memory
> > > usage :
> > > 
> > >     daevel-ob@ssdr712g:~$ ps auxw | grep ceph-osd
> > >     ceph        6287  6.6 10.6 6027388 5190032 ?     Ssl  mars21
> > > 1511:07 /usr/bin/ceph-osd -f --cluster ceph --id 131 --setuser
> > > ceph --setgroup ceph
> > >     ceph        6759  7.3 11.2 6299140 5484412 ?     Ssl  mars21
> > > 1665:22 /usr/bin/ceph-osd -f --cluster ceph --id 132 --setuser
> > > ceph --setgroup ceph
> > >     ceph        7114  7.0 11.7 6576168 5756236 ?     Ssl  mars21
> > > 1612:09 /usr/bin/ceph-osd -f --cluster ceph --id 133 --setuser
> > > ceph --setgroup ceph
> > >     ceph        7467  7.4 11.1 6244668 5430512 ?     Ssl  mars21
> > > 1704:06 /usr/bin/ceph-osd -f --cluster ceph --id 134 --setuser
> > > ceph --setgroup ceph
> > >     ceph        7821  7.7 11.1 6309456 5469376 ?     Ssl  mars21
> > > 1754:35 /usr/bin/ceph-osd -f --cluster ceph --id 135 --setuser
> > > ceph --setgroup ceph
> > >     ceph        8174  6.9 11.6 6545224 5705412 ?     Ssl  mars21
> > > 1590:31 /usr/bin/ceph-osd -f --cluster ceph --id 136 --setuser
> > > ceph --setgroup ceph
> > >     ceph        8746  6.6 11.1 6290004 5477204 ?     Ssl  mars21
> > > 1511:11 /usr/bin/ceph-osd -f --cluster ceph --id 137 --setuser
> > > ceph --setgroup ceph
> > >     ceph        9100  7.7 11.6 6552080 5713560 ?     Ssl  mars21
> > > 1757:22 /usr/bin/ceph-osd -f --cluster ceph --id 138 --setuser
> > > ceph --setgroup ceph
> > > 
> > >     But ! On a similar host, in a different pool, the problem is
> > > less visible :
> > > 
> > >     daevel-ob@ssdr712i:~$ ps auxw | grep ceph-osd
> > >     ceph        3617  2.8  9.9 5660308 4847444 ?     Ssl  mars29
> > > 313:05 /usr/bin/ceph-osd -f --cluster ceph --id 151 --setuser
> > > ceph --setgroup ceph
> > >     ceph        3958  2.3  9.8 5661936 4834320 ?     Ssl  mars29
> > > 256:55 /usr/bin/ceph-osd -f --cluster ceph --id 152 --setuser
> > > ceph --setgroup ceph
> > >     ceph        4299  2.3  9.8 5620616 4807248 ?     Ssl  mars29
> > > 266:26 /usr/bin/ceph-osd -f --cluster ceph --id 153 --setuser
> > > ceph --setgroup ceph
> > >     ceph        4643  2.3  9.6 5527724 4713572 ?     Ssl  mars29
> > > 262:50 /usr/bin/ceph-osd -f --cluster ceph --id 154 --setuser
> > > ceph --setgroup ceph
> > >     ceph        5016  2.2  9.7 5597504 4783412 ?     Ssl  mars29
> > > 248:37 /usr/bin/ceph-osd -f --cluster ceph --id 155 --setuser
> > > ceph --setgroup ceph
> > >     ceph        5380  2.8  9.9 5700204 4886432 ?     Ssl  mars29
> > > 321:05 /usr/bin/ceph-osd -f --cluster ceph --id 156 --setuser
> > > ceph --setgroup ceph
> > >     ceph        5724  3.1 10.1 5767456 4953484 ?     Ssl  mars29
> > > 352:55 /usr/bin/ceph-osd -f --cluster ceph --id 157 --setuser
> > > ceph --setgroup ceph
> > >     ceph        6070  2.7  9.9 5683092 4868632 ?     Ssl  mars29
> > > 309:10 /usr/bin/ceph-osd -f --cluster ceph --id 158 --setuser
> > > ceph --setgroup ceph
> > > 
> > > 
> > >     Is there some memory leak ? Or should I expect that
> > > osd_memory_target
> > >     (the default 4GB here) is not really followed, and so reduce
> > > it ?
> > > 
> > >     Thanks,
> > > 
> > > 
> > > _______________________________________________
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