13 Jan
2020
13 Jan
'20
12:42 p.m.
Hi Casey, Igor
thank you for your response
Casey:
This cluster is secondary zone in Multi-Site setup (placement pools have
been set as "default.")
[root@mon-1 ~]# radosgw-admin zone get
{
"id": "96b9adcb-fdc0-4f36-a310-89347b74ea67",
"name": "secondary_zone",
"placement_pools": [
{
"key": "default-placement",
"val": {
"index_pool": "default.rgw.buckets.index",
Igor:
All of the osd are backed by bluestore. There are NVME disks dedicated for
index pool. I dont use separated db and wal devices.
Creation command: ceph-volume --cluster ceph lvm create --bluestore --data
/dev/nvme0n1p9
These osds were deployed in Mimic (v13.2.5).
Last Friday, i upgraded cluster to 14.2.6, and I purged and recreated this
osd. And I don't see this problem anymore.
I hope this helped.
Below, I paste the result of debugging the problem:
1) listing omap keys
[root@mon-1 ~]# time rados -p default.rgw.buckets.index listomapkeys
.dir.99a07ed8-2112-429b-9f94-81383220a95b.33721775.254244.31 > omapkeys.list
real 0m29.475s
user 0m0.123s
sys 0m0.131s
[root@osd-n57 ~]# tail -f /var/log/ceph/ceph-osd.62.log |grep "slow
operation "
2020-01-10 09:50:36.274 7f1fa22dd700 0
bluestore(/var/lib/ceph/osd/ceph-62) log_latency slow operation observed
for next, latency = 29.0901s
2) listing omap vals
[dc-2 root@mon-1 tmp]# time rados -p default.rgw.buckets.index listomapvals
.dir.99a07ed8-2112-429b-9f94-81383220a95b.33721775.254244.31 > omapvals.list
real 0m29.080s
user 0m2.801s
sys 0m0.270s
[root@osd-n57 ~]# tail -f /var/log/ceph/ceph-osd.62.log |grep "slow
operation "
2020-01-10 09:52:37.164 7f1fa22dd700 0
bluestore(/var/lib/ceph/osd/ceph-62) log_latency slow operation observed
for next, latency = 25.6445s
3) listing bilogs for this bucket (ID:
99a07ed8-2112-429b-9f94-81383220a95b.33721775.254244)
[root@mon-1 ~]# radosgw-admin bilog list --bucket bucket_1 #(the same
effect)
[root@osd-n57 ~]# tail -f /var/log/ceph/ceph-osd.62.log |grep "slow
operation "
2020-01-10 10:01:27.896 7f1fa62e5700 0
bluestore(/var/lib/ceph/osd/ceph-62) log_latency_fn slow operation observed
for upper_bound, latency = 26.7958s, after = �0_ omap_iterator(cid =
230.2c_head, oid =
#230:36f53ff9:::.dir.99a07ed8-2112-429b-9f94-81383220a95b.33721775.254244.31:head#)
2020-01-10 10:01:28.981 7f1fbfb18700 -1 osd.62 23457 get_health_metrics
reporting 2 slow ops, oldest is osd_op(client.200549558.0:308265358 230.2c
230:35a96e8b:::.dir.99a07ed8-2112-429b-9f94-81383220a95b.49439529.1.85:head
[call rgw.bi_log_trim] snapc 0=[] ondisk+write+known_if_redirected e23457)
4) bilogs GC, while trimming bucket index logs from this bucket:
.dir.99a07ed8-2112-429b-9f94-81383220a95b.33721775.254244.31 (the same
effect) as above
I checked that a lot of operations in cluster are blocked while some other
process is touching omap shard:
.dir.99a07ed8-2112-429b-9f94-81383220a95b.33721775.254244.31.
For example s3cmd listing:
First scenario: List objects from random bucket, with using s3cmd.
[root@po:~ ]$ time s3cmd -c .s3cfg.n123 --no-ssl ls s3://bucket_n123/
--limit 1 -r
2019-09-10 10:38 511600 s3://bucket_n123/BnxKLbY2mN7Jw5b4pdkiU.jpg
real 0m0,244s
user 0m0,142s
sys 0m0,041s
Second scenario: List objects from random bucket, with using s3cmd +
listing omapkeys
of.dir.99a07ed8-2112-429b-9f94-81383220a95b.33721775.254244.31 (at the same
time):
[root@mon-1 ~]# time rados -p default.rgw.buckets.index listomapkeys
.dir.99a07ed8-2112-429b-9f94-81383220a95b.33721775.254244.31
[root@po:~ ]$ time s3cmd -c .s3cfg.n123 --no-ssl ls s3://bucket_n123/
--limit 1 -r
2019-09-10 10:38 511600 s3://bucket_n123/BnxKLbY2mN7Jw5b4pdkiU.jpg
real 0m25,802s
user 0m0,211s
sys 0m0,040s
[root@osd-n57 ~]# tail -f /var/log/ceph/ceph-osd.62.log |grep "slow
operation "
2020-01-10 10:08:40.942 7f1fbfb18700 -1 osd.62 23480 get_health_metrics
reporting 60 slow ops, oldest is osd_op(client.200549558.0:313502542 230.2c
230:34aaa3d7:::.dir.99a07ed8-2112-429b-9f94-81383220a95b.51788790.1.2:head
[call rgw.guard_bucket_resharding,call rgw.bucket_prepare_op] snapc 0=[]
ondisk+write+known_if_redirected e23480)
Thanks,
Piotr
pt., 10 sty 2020 o 15:30 Igor Fedotov <ifedotov(a)suse.de> napisał(a):
Hi Piotr,
wondering what's the device layout behind OSD/Bluestore? Do you have fast
(SSD or NVMe) standalone device for DB/WAL at slow OSDs? Were OSDs in
question deployed in Nautilus or do they originate from the earlier Ceph
releases?
We've got multiple reports about slow omap operations at different
clusters from our customers. In every case one had rotational-only (!)
media behind OSD and RGW payload. I.e. slow DB device and high amount of
metadata going to RocksDB. And behavior most likely was triggered by a
massive prior data removal. Looks like RocksDB behind BlueStore has some
performance gaps when dealing with highly fragmented DB at slow media.
Nautilus has got some improvements in this respect but chances are this
isn't enough.
Manual RocksDB compaction seems to be a short-term workaround if the above
is applicable. And the general advise would be to have faster device for DB.
Thanks,
Igor
PS. The above doesn't mean that RGW is out of corresponding errors or/and
is absolutely optimal. Most probably it has some areas for improvement
which might resolve the issue as well. Which is likely to be an alternative
approach for the fix. But I'm not aware of them.
PS 2. Potentially the same RocksDB slowdown might also occur if OSD has
large DB data spillover from fast DB device to slow main one. Nautilus has
corresponding alerts available via ceph -s / ceph health commands.
On 1/9/2020 6:33 PM, P. O. wrote:
Hi All,
I am observing strange behaviour on one OSD, which is dedicated for RGW
index (pool: default.rgw.buckets.index).
My ceph is: ceph version 14.2.4 (75f4de193b3ea58512f204623e6c5a16e6c1e1ba)
nautilus (stable)
In log files are many messages like below:
2020-01-08 10:37:53.054 7f1fa22dd700 0
bluestore(/var/lib/ceph/osd/ceph-62) log_latency slow operation observed
for next, latency = 22.4641s
...
2020-01-08 14:57:06.987 7f1fa22dd700 0
bluestore(/var/lib/ceph/osd/ceph-62) log_latency_fn slow operation observed
for upper_bound, latency = 28.9336s, after = �0_ omap_iterator(cid =
230.2c_head, oid =
#230:36f53ff9:::.dir.12307ed8-2342-4293-9f14-12234220a234.13221775.224244.31:head#)
2020-01-08 15:17:39.972 7f1fa22dd700 0
bluestore(/var/lib/ceph/osd/ceph-62) log_latency_fn slow operation observed
for upper_bound, latency = 23.9168s, after = �0_ omap_iterator(cid =
230.2c_head, oid =
#230:36f53ff9:::.dir.12307ed8-2342-4293-9f14-12234220a234.13221775.224244.31:head#)
2020-01-08 15:37:44.221 7f1fa62e5700 0
bluestore(/var/lib/ceph/osd/ceph-62) log_latency_fn slow operation observed
for upper_bound, latency = 25.8316s, after = �0_ omap_iterator(cid =
230.2c_head, oid =
#230:36f53ff9:::.dir.12307ed8-2342-4293-9f14-12234220a234.13221775.224244.31:head#)
2020-01-08 15:58:12.279 7f1fa62e5700 0
bluestore(/var/lib/ceph/osd/ceph-62) log_latency_fn slow operation observed
for upper_bound, latency = 27.8207s, after = �0_ omap_iterator(cid =
230.2c_head, oid =
#230:36f53ff9:::.dir.12307ed8-2342-4293-9f14-12234220a234.13221775.224244.31:head#)
I discovered that these times are associated with GC bilogs (it runs every
30 minutes).
# /etc/ceph/ceph.conf
rgw sync log trim interval = 1200
ID of bucket bucket_1: 12307ed8-2342-4293-9f14-12234220a234.13221775.224244
Shard nr. 31 of bucket (bucket_1) index:
.dir.12307ed8-2342-4293-9f14-12234220a234.13221775.224244.31
[root@mon-1 ~]# ceph osd map default.rgw.buckets.index
.dir.12307ed8-2342-4293-9f14-12234220a234.13221775.224244.31
osdmap e23417 pool 'default.rgw.buckets.index' (230) object
'.dir.12307ed8-2342-4293-9f14-12234220a234.13221775.224244.31' -> pg
230.9ffcaf6c (230.2c) -> up ([62,56,60], p62) acting ([62,56,60], p62)
OSD: 62,56,60
Problematic OSD: 62
Problematic PG: 230.2c
digging deeper..
I checked that when I run the command:
[root@mon-1 ~]# radosgw-admin bilog list --bucket bucket_1
[]
Even when there are no bilogs, there are the same symptoms:
1) In logs:
2020-01-08 16:31:24.728 7f1fa22dd700 0
bluestore(/var/lib/ceph/osd/ceph-62) log_latency_fn slow operation observed
for upper_bound, latency = 28.653s, after = �0_ omap_iterator(cid =
230.2c_head, oid =
#230:36f53ff9:::.dir.12307ed8-2342-4293-9f14-12234220a234.13221775.224244.31:head#)
2) Any other radosgw-admin commands are very slow while other process is
iterating through bilogs (of this bucket).
[dc-2 root@mon-1 ~]# time radosgw-admin bucket stats --bucket=bucket234
...
real 0m25.641s
user 0m0.148s
sys 0m0.075s
When i try to run deep scrub on this pg 230.2c, in logs appears:
[root@mon-1 ~]# ceph pg deep-scrub 230.2c
2020-01-08 16:38:32.551 7f1fc50f0700 1 heartbeat_map is_healthy
'OSD::osd_op_tp thread 0x7f1fa22dd700' had timed out after 15
...
2020-01-08 16:38:46.735 7f1fc60f2700 1 heartbeat_map is_healthy
'OSD::osd_op_tp thread 0x7f1fa62e5700' had timed out after 15
2020-01-08 16:38:46.735 7f1fc60f2700 1 heartbeat_map is_healthy
'OSD::osd_op_tp thread 0x7f1fa22dd700' had timed out after 15
2020-01-08 16:38:46.735 7f1fc60f2700 1 heartbeat_map is_healthy
'OSD::osd_op_tp thread 0x7f1fa62e5700' had timed out after 15
2020-01-08 16:38:46.911 7f1fa22dd700 0
bluestore(/var/lib/ceph/osd/ceph-62) log_latency_fn slow operation observed
for upper_bound, latency = 29.8655s, after = <80>0_ omap_iterator(cid =
230.2c_head, oid =
#230:36f53ff9:::.dir.12307ed8-2342-4293-9f14-12234220a234.13221775.224244.31:head#)
2020-01-08 16:38:46.911 7f1fa22dd700 1 heartbeat_map reset_timeout
'OSD::osd_op_tp thread 0x7f1fa22dd700' had timed out after 15
2020-01-08 16:38:46.911 7f1fa62e5700 1 heartbeat_map reset_timeout
'OSD::osd_op_tp thread 0x7f1fa62e5700' had timed out after 15
2020-01-08 10:37:53.054 7f1fa22dd700 0
bluestore(/var/lib/ceph/osd/ceph-62) log_latency slow operation observed
for next, latency = 22.4641s
When i try to iterate over listomapkeys for:
.dir.12307ed8-2342-4293-9f14-12234220a234.13221775.224244.31
[root@mon-1 ~]# rados -p default.rgw.buckets.index listomapkeys
.dir.12307ed8-2342-4293-9f14-12234220a234.13221775.224244.31
In logs i observe:
2020-01-09 11:08:58.847 7f1fa62e5700 0
bluestore(/var/lib/ceph/osd/ceph-62) log_latency slow operation observed
for next, latency = 24.1949s
The same for listomapvals
[root@mon-1 ~]# rados -p default.rgw.buckets.index listomapvals
.dir.12307ed8-2342-4293-9f14-12234220a234.13221775.224244.31
2020-01-09 11:11:36.508 7f1fa62e5700 0
bluestore(/var/lib/ceph/osd/ceph-62) log_latency slow operation observed
for next, latency = 28.2137s
I tried to purge and recreate this OSD, also I trimmed bilogs for this
bucket (radosgw-admin bilog trim --bucket bucket_1), but this didn't help.
I suspect that any operations on PG: 230.2c on OSD: 62 can causing slow
operations on my cluster.
I have no idea how to debug/resolve this problem. Any help/hint is
appreciated!
Thanks,
Piotr
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