I'm going to piggy back on this somewhat.
I've battled RocksDB spillovers over the course of the life of the
cluster since moving to bluestore, however I have always been able
to compact it well enough.
But now I am stumped at getting this to compact via $ceph tell
osd.$osd compact, which has always worked in the past.
No matter how many times I compact it, I always spill over exactly
192KiB.
BLUEFS_SPILLOVER BlueFS spillover detected on 1 OSD(s)
osd.36 spilled over 192 KiB metadata from 'db' device (26 GiB
used of 34 GiB) to slow device
osd.36 spilled over 192 KiB metadata from 'db' device (16 GiB
used of 34 GiB) to slow device
osd.36 spilled over 192 KiB metadata from 'db' device (22 GiB
used of 34 GiB) to slow device
osd.36 spilled over 192 KiB metadata from 'db' device (13 GiB
used of 34 GiB) to slow device
The multiple entries are from different time trying to compact it.
The OSD is a 1.92TB SATA SSD, the WAL/DB is a 36GB partition on NVMe.
I tailed and tee'd the OSD's logs during a manual compaction here:
https://pastebin.com/bcpcRGEe
This is with the normal logging level.
I have no idea how to make heads or tails of that log data, but
maybe someone can figure out why this one OSD just refuses to compact?
OSD is 14.2.9.
OS is U18.04.
Kernel is 4.15.0-96.
I haven't played with ceph-bluestore-tool or ceph-kvstore-tool but
after seeing the above mention in this thread, I do see
ceph-kvstore-tool <rocksdb|bluestore-kv?> compact, which sounds like
it may be the same thing that ceph tell compact does under the hood?
compact
Subcommand compact is used to compact all data of kvstore. It will
open the database, and trigger a database's compaction. After
compaction, some disk space may be released.
Also, not sure if this is helpful:
osd.36 spilled over 192 KiB metadata from 'db' device (13 GiB used
of 34 GiB) to slow device
ID CLASS WEIGHT REWEIGHT SIZE RAW USE DATA OMAP META
AVAIL %USE VAR PGS STATUS TYPE NAME
36 ssd 1.77879 1.00000 1.8 TiB 1.2 TiB 1.2 TiB 6.2 GiB 7.2
GiB 603 GiB 66.88 0.94 85 up osd.36
You can see the breakdown between OMAP data and META data.
After compacting again:
osd.36 spilled over 192 KiB metadata from 'db' device (26 GiB used
of 34 GiB) to slow device
ID CLASS WEIGHT REWEIGHT SIZE RAW USE DATA OMAP META
AVAIL %USE VAR PGS STATUS TYPE NAME
36 ssd 1.77879 1.00000 1.8 TiB 1.2 TiB 1.2 TiB 6.2 GiB 20
GiB 603 GiB 66.88 0.94 85 up osd.36
So the OMAP size remained the same, while the metadata ballooned
(while still conspicuously spilling over 192KiB exactly)
These OSDs have a few RBD images, cephfs metadata, and librados
objects (not RGW) stored.
The breakdown of OMAP size is pretty widely binned, but the GiB
sizes are definitely the minority.
Looking at the breakdown with some simple bash-fu
KiB = 147
MiB = 105
GiB = 24
To further divide that, all of the GiB sized OMAPs are SSD OSD's:
*SSD*
*HDD*
*TOTAL*
*KiB*
0
147
147
*MiB*
36
69
105
*GiB*
24
0
24
I have no idea if any of these data points are pertinent or helpful,
but I want to give as clear a picture as possible to prevent chasing
the wrong thread.
Appreciate any help with this.
Thanks,
Reed
On May 26, 2020, at 9:48 AM, thoralf schulze
<t.schulze@xxxxxxxxxxxx <mailto:t.schulze@xxxxxxxxxxxx>> wrote:
hi there,
trying to get around my head rocksdb spillovers and how to deal with
them … in particular, i have one osds which does not have any pools
associated (as per ceph pg ls-by-osd $osd ), yet it does show up in
ceph
health detail as:
osd.$osd spilled over 2.9 MiB metadata from 'db' device (49 MiB
used of 37 GiB) to slow device
compaction doesn't help. i am well aware of
https://tracker.ceph.com/issues/38745 , yet find it really
counter-intuitive that an empty osd with a more-or-less optimal
sized db
volume can't fit its rockdb on the former.
is there any way to repair this, apart from re-creating the osd? fwiw,
dumping the database with
ceph-kvstore-tool bluestore-kv /var/lib/ceph/osd/ceph-$osd dump >
bluestore_kv.dump
yields a file of less than 100mb in size.
and, while we're at it, a few more related questions:
- am i right to assume that the leveldb and rocksdb arguments to
ceph-kvstore-tool are only relevant for osds with filestore-backend?
- does ceph-kvstore-tool bluestore-kv … also deal with
rocksdb-items for
osds with bluestore-backend?
thank you very much & with kind regards,
thoralf.
_______________________________________________
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 toceph-users-leave@xxxxxxx
