|
>> >
>> >cephfs does not create/use object "4.00000000". Please show us some
>> >of its keys.
>> >
>>
>> Thanks
>>
> Is the object recently modified?
>
>rados -p hpcfs_metadata stat 4.00000000
>
$ rados -p hpcfs_metadata stat 4.00000000
hpcfs_metadata/4.00000000 mtime 2018-09-17 08:11:50.000000, size 0
>> >On Mon, Mar 18, 2019 at 4:16 PM Dylan McCulloch <dmc@xxxxxxxxxxxxxx> wrote:
>> >>
>> >> Hi all,
>> >>
>> >> We have a large omap object warning on one of our Ceph clusters.
>> >> The only reports I've seen regarding the "large omap objects" warning from other users were related to RGW bucket sharding, however we do not have RGW configured on this cluster.
>> >> The large omap object ~10GB resides in a CephFS metadata pool.
>> >>
>> >> It's perhaps worth mentioning that we had to perform disaster recovery steps [1] on this cluster last year after a network issue, so we're not sure whether this large omap object is a result of those previous recovery processes or whether it's completely
unrelated.
>> >>
>> >> Ceph version: 12.2.8
>> >> osd_objectstore: Bluestore
>> >> RHEL 7.5
>> >> Kernel: 4.4.135-1.el7.elrepo.x86_64
>> >>
>> >> We have set: "mds_bal_fragment_size_max": "500000" (Default 100000)
>> >>
>> >> $ ceph health detail
>> >> HEALTH_WARN 1 large omap objects
>> >> LARGE_OMAP_OBJECTS 1 large omap objects
>> >> 1 large objects found in pool 'hpcfs_metadata'
>> >> Search the cluster log for 'Large omap object found' for more details.
>> >>
>> >> # Find pg with large omap object
>> >> $ for i in `ceph pg ls-by-pool hpcfs_metadata | tail -n +2 | awk '{print $1}'`; do echo -n "$i: "; ceph pg $i query |grep num_large_omap_objects | head -1 | awk '{print $2}'; done | grep ": 1"
>> >> 20.103: 1
>> >>
>> >> # OSD log entry showing relevant object
>> >> osd.143 osd.143 172.26.74.23:6826/3428317 1380 : cluster [WRN] Large omap object found. Object: 20:c0ce80d4:::4.00000000:head Key count: 24698995 Size (bytes): 11410935690
>> >>
>> >> # Confirm default warning thresholds for large omap object
>> >> $ ceph daemon osd.143 config show | grep osd_deep_scrub_large_omap
>> >> "osd_deep_scrub_large_omap_object_key_threshold": "2000000",
>> >> "osd_deep_scrub_large_omap_object_value_sum_threshold": "1073741824",
>> >>
>> >> # Dump keys/values of problematic object, creates 46.65GB file
>> >> $ rados -p hpcfs_metadata listomapvals '4.00000000' > /tmp/hpcfs_metadata_object_omap_vals_4.00000000_20190304
>> >> $ ll /tmp/hpcfs_metadata_object_omap_vals_4.00000000_20190304
>> >> -rw-r--r-- 1 root root 50089561860 Mar 4 18:16 /tmp/hpcfs_metadata_object_omap_vals_4.00000000_20190304
>> >>
>> >> # Confirm key count matches OSD log entry warning
>> >> $ rados -p hpcfs_metadata listomapkeys '4.00000000' | wc -l
>> >> 24698995
>> >>
>> >> # The omap keys/vals for that object appear to have been unchanged/static for at least a couple of months:
>> >> $ sha1sum /tmp/hpcfs_metadata_object_omap_vals_4.00000000_20190304
>> >> fd00ceb68607b477626178b2d81fefb926460107 /tmp/hpcfs_metadata_object_omap_vals_4.00000000_20190304
>> >> $ sha1sum /tmp/hpcfs_metadata_object_omap_vals_4_00000000_20190108
>> >> fd00ceb68607b477626178b2d81fefb926460107 /tmp/hpcfs_metadata_object_omap_vals_4_00000000_20190108
>> >>
>> >> I haven't gone through all 24698995 keys yet, but while most appear to relate to objects in the hpcfs_data CephFS data pool, there are a significant number of keys (rough guess 25%) that don't appear to have corresponding objects in the hpcfs_data
pool.
>> >>
>> >> Any assistance or pointers to troubleshoot further would be very much appreciated.
>> >>
>> >> Thanks,
>> >> Dylan
>> >>
>> >>
>> >> _______________________________________________
>> >> ceph-users mailing list
>> >> ceph-users@xxxxxxxxxxxxxx
>> >>
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