Re: LARGE_OMAP_OBJECTS: any proper action possible?

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Those are probably large directories; each omap key is a file/subdir
in the directory.

Normally the mds fragments dirs across several objects, so you
shouldn't have a huge number of omap entries in any one single object.
Do you have some custom mds config in this area?

-- dan

On Wed, Aug 25, 2021 at 2:01 PM Frank Schilder <frans@xxxxxx> wrote:
>
> Hi Dan,
>
> thanks for looking at this. Here are the lines from health detail and ceph.log:
>
> [root@gnosis ~]# ceph health detail
> HEALTH_WARN 4 large omap objects
> LARGE_OMAP_OBJECTS 4 large omap objects
>     4 large objects found in pool 'con-fs2-meta1'
>     Search the cluster log for 'Large omap object found' for more details.
>
> The search gives:
>
> 2021-08-25 11:17:00.675474 osd.21 osd.21 192.168.32.77:6846/12302 651 : cluster [WRN] Large omap object found. Object: 12:373fb013:::1000eec35f5.01000000:head PG: 12.c80dfcec (12.6c) Key count: 216000 Size (bytes): 101520000
> 2021-08-25 11:17:06.866726 osd.37 osd.37 192.168.32.77:6850/12306 644 : cluster [WRN] Large omap object found. Object: 12:05982a7e:::1000d7fd167.02800000:head PG: 12.7e5419a0 (12.20) Key count: 2293816 Size (bytes): 1078093520
> 2021-08-25 11:17:11.152671 osd.37 osd.37 192.168.32.77:6850/12306 645 : cluster [WRN] Large omap object found. Object: 12:05da1450:::1000e118c0a.00000000:head PG: 12.a285ba0 (12.20) Key count: 220612 Size (bytes): 103687640
> 2021-08-25 11:17:36.603664 osd.36 osd.36 192.168.32.75:6848/11882 1243 : cluster [WRN] Large omap object found. Object: 12:0b298d19:::1000eec35f7.04e00000:head PG: 12.98b194d0 (12.50) Key count: 657212 Size (bytes): 308889640
>
> They are all in the fs meta-data pool.
>
> Best regards,
> =================
> Frank Schilder
> AIT Risø Campus
> Bygning 109, rum S14
>
> ________________________________________
> From: Dan van der Ster <dan@xxxxxxxxxxxxxx>
> Sent: 25 August 2021 13:57:44
> To: Frank Schilder
> Cc: ceph-users
> Subject: Re:  LARGE_OMAP_OBJECTS: any proper action possible?
>
> Hi Frank,
>
> Which objects are large? (You should see this in ceph.log when the
> large obj was detected).
>
> -- dan
>
> On Wed, Aug 25, 2021 at 12:27 PM Frank Schilder <frans@xxxxxx> wrote:
> >
> > Hi all,
> >
> > I have the notorious "LARGE_OMAP_OBJECTS: 4 large omap objects" warning and am again wondering if there is any proper action one can take except "wait it out and deep-scrub (numerous ceph-users threads)" or "ignore (https://docs.ceph.com/en/latest/rados/operations/health-checks/#large-omap-objects)". Only for RGWs is a proper action described, but mine come from MDSes. Is there any way to ask an MDS to clean up or split the objects?
> >
> > The disks with the meta-data pool can easily deal with objects of this size. My question is more along the lines: If I can't do anything anyway, why the warning? If there is a warning, I would assume that one can do something proper to prevent large omap objects from being born by an MDS. What is it?
> >
> > Best regards,
> > =================
> > Frank Schilder
> > AIT Risø Campus
> > Bygning 109, rum S14
> > _______________________________________________
> > ceph-users mailing list -- ceph-users@xxxxxxx
> > To unsubscribe send an email to ceph-users-leave@xxxxxxx
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