From https://swamireddy.wordpress.com/2019/10/23/ceph-sharding-the-rados-gateway-... *Since the index is stored in a single RADOS object, only a single operation can be done on it at any given time. When the number of objects increases, the index stored in the RADOS object grows. Since a single index is handling a large number of objects, and there is a chance the number of operations also increases, parallelism is not possible which can end up being a bottleneck. Multiple operations will need to wait in a queue since a single operation is possible at a time.* Maybe you know, is this still the case? Article is from 2019. On Sun, Jun 25, 2023 at 6:22 PM Szabo, Istvan (Agoda) < Istvan.Szabo@agoda.com> wrote:
Hi,
Can you check the read and write latency of your osds? Maybe it hangs because it’s waiting for pg’s but maybe the pg are under scrub or something else. Also with many small objects don’t rely on pg autoscaler, it might not tell to increase pg but maybe it should be.
Istvan Szabo Staff Infrastructure Engineer --------------------------------------------------- Agoda Services Co., Ltd. e: istvan.szabo@agoda.com ---------------------------------------------------
On 2023. Jun 23., at 19:12, Rok Jaklič <rjaklic@gmail.com> wrote:
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We are experiencing something similar (slow GETs responses) when sending 1k delete requests for example in ceph v16.2.13.
Rok
On Mon, Jun 12, 2023 at 7:16 PM grin <grin@grin.hu> wrote:
Hello,
ceph version 17.2.6 (d7ff0d10654d2280e08f1ab989c7cdf3064446a5) quincy
(stable)
There is a single (test) radosgw serving plenty of test traffic. When
under heavy req/s ("heavy" in a low sense, about 1k rq/s) it pretty
reliably hangs: low traffic threads seem to work (like handling occasional
PUTs) but GETs are completely nonresponsive, all attention seems to be
spent on futexes.
The effect is extremely similar to
https://ceph-users.ceph.narkive.com/I4uFVzH9/radosgw-civetweb-hangs-once-aro...
(subject: Radosgw (civetweb) hangs once around)
except this is quincy so it's beast instead of civetweb. The effect is the
same as described there, except the cluster is way smaller (about 20-40
OSDs).
I observed that when I start radosgw -f with debug 20/20 it almost never
hangs, so my guess is some ugly race condition. However I am a bit clueless
how to actually debug it since debugging makes it go away. Debug 1
(default) with -d seems to hang after a while but it's not that simple to
induce, I'm still testing under 4/4.
Also I do not see much to configure about beast.
As to answer the question in the original (2016) thread:
- Debian stable
- no visible limits issue
- no obvious memory leak observed
- no other visible resource shortage
- strace says everyone's waiting on futexes, about 600-800 threads, apart
from the one serving occasional PUTs
- tcp port doesn't respond.
IRC didn't react. ;-)
Thanks,
Peter
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