Hi,
Josh already suggested, but I will one more time. We had similar
behaviour upgrading from Nautilus to Pacific. In our case compacting the
OSDs did the trick.
For us there was no performance impact running the compaction (ceph osd
daemon osd.0 compact) although we run them in batches and not all at
once on all OSDs just in case. Also, no need to restart OSDs for this
operation.
https://www.spinics.net/lists/ceph-users/msg74774.html
Regards,
Ana
On 30-01-2023 10:23, Victor Rodriguez wrote:
I'm reading that thread on spinics. Thanks for pointing that out.
The cluster was upgraded from Nautilus to Octopus first week of
December. No previous version has been used in this cluster. I just
don't remember if we used snapshots after the upgrade.
bluestore_fsck_quick_fix_on_mount is at default of "true". Did not
notice anything unusual during or after the upgrade.
Is there any way to check if the OMAP conversion is done for an OSD?
Maybe it tries to do the conversion every time I restart an OSD and
fails? (given they take nearly a minute to start). I still have 13 PGs
pending snaptrims and client I/O is severely affected even while doing
on OSD at a time and osd_snap_trim_sleep_ssd=5 :\
On 1/30/23 09:23, Frank Schilder wrote:
Hi Victor,
out of curiosity, did you upgrade the cluster recently to octopus? We
and others observed this behaviour when following one out of two
routes to upgrade OSDs. There was a thread "Octopus OSDs extremely
slow during upgrade from mimic", which seems to have been lost with
the recent mail list outage. If it is relevant, I could copy pieces I
have into here.
Best regards,
=================
Frank Schilder
AIT Risø Campus
Bygning 109, rum S14
________________________________________
From: Victor Rodriguez <vrodriguez@xxxxxxxxxxxxx>
Sent: 29 January 2023 22:40:46
To: ceph-users@xxxxxxx
Subject: Re: Very slow snaptrim operations blocking
client I/O
Looks like this is going to take a few days. I hope to manage the
available performance for VMs with osd_snap_trim_sleep_ssd.
I'm wondering if after that long snaptrim process you went through, was
your cluster was stable again and snapshots/snaptrims did work properly?
On 1/29/23 16:01, Matt Vandermeulen wrote:
I should have explicitly stated that during the recovery, it was still
quite bumpy for customers. Some snaptrims were very quick, some took
what felt like a really long time. This was however a cluster with a
very large number of volumes and a long, long history of snapshots.
I'm not sure what the difference will be from our case versus a single
large volume with a big snapshot.
On 2023-01-28 20:45, Victor Rodriguez wrote:
On 1/29/23 00:50, Matt Vandermeulen wrote:
I've observed a similar horror when upgrading a cluster from
Luminous to Nautilus, which had the same effect of an overwhelming
amount of snaptrim making the cluster unusable.
In our case, we held its hand by setting all OSDs to have zero max
trimming PGs, unsetting nosnaptrim, and then slowly enabling
snaptrim a few OSDs at a time. It was painful to babysit but it
allowed the cluster to catch up without falling over.
That's an interesting approach! Thanks!
On preliminary tests seems that just running snaptrim on a single PG
of a single OSD still makes the cluster barely usable. I have to
increase osd_snap_trim_sleep_ssd to ~1 so the cluster remains usable
by getting a third of its performance. After a while, a few PG got
trimmed and feels like some of them are harder to trim than others,
as some need a higher osd_snap_trim_sleep_ssd value to let the
cluster perform.
I don't know how long this is going to take... Maybe recreating the
OSD's and dealing with the rebalance is a better option?
There's something ugly going on here... I would really like to put my
finger on it.
On 2023-01-28 19:43, Victor Rodriguez wrote:
After some investigation this is what I'm seeing:
- OSD processes get stuck at least at 100% CPU if I ceph osd unset
nosnaptrim. They keep at 100% CPU even if I ceph osd set
nosnaptrim. They stayed like that for at least 26 hours. Some quick
benchmarks don't show a reduction of the performance of the cluster.
- Restarting a OSD lowers it's CPU usage to typical levels, as
expected, but it also usually sets some other OSD in a different
host to typical levels.
- All OSDs in this cluster take quite a bit to start: between 35 to
70 seconds depending on the OSD. Clearly much longer than any other
OSD in any of my clusters.
- I believe that the size of the rocksdb database is dumped in the
OSD log when an automatic compact operation is triggered. The "sum"
sizes of these OSD range between 2.5 and 5.1 GB. Thats way bigger
that those in any other cluster I have.
- ceph daemon osd.* calc_objectstore_db_histogram is giving values
for num_pgmeta_omap (I don't know what it is) way bigger than those
on any other of my clusters for some OSD. Also, values are not
similar among the OSD which hold the same PGs.
osd.0: "num_pgmeta_omap": 17526766,
osd.1: "num_pgmeta_omap": 2653379,
osd.2: "num_pgmeta_omap": 12358703,
osd.3: "num_pgmeta_omap": 6404975,
osd.6: "num_pgmeta_omap": 19845318,
osd.7: "num_pgmeta_omap": 6043083,
osd.12: "num_pgmeta_omap": 18666776,
osd.13: "num_pgmeta_omap": 615846,
osd.14: "num_pgmeta_omap": 13190188,
- Compacting the OSD barely reduces rocksdb size and does not
reduce num_pgmeta_omap at all.
- This is the only cluster I have were there are some RBD images
that I mount directly from some clients, that is, they are not
disks for QEMU/Proxmox VMs. Maybe I have something misconfigured
related to this? This cluster is at least two and half years old
an never had this issue with snaptrims.
Thanks in advance!
_______________________________________________
ceph-users mailing list -- ceph-users@xxxxxxx
To unsubscribe send an email to ceph-users-leave@xxxxxxx
--
_______________________________________________
ceph-users mailing list -- ceph-users@xxxxxxx
To unsubscribe send an email to ceph-users-leave@xxxxxxx
_______________________________________________
ceph-users mailing list -- ceph-users@xxxxxxx
To unsubscribe send an email to ceph-users-leave@xxxxxxx
