Thank you Eugen for your warm help! I'm trying to understand the difference between 2 methods. For method 1, or "ceph orch osd rm osd_id", OSD Service — Ceph Documentation <https://docs.ceph.com/en/latest/cephadm/services/osd/#remove-an-osd> says it involves 2 steps: 1. evacuating all placement groups (PGs) from the OSD 2. removing the PG-free OSD from the cluster For method 2, or the procedure you recommended, Adding/Removing OSDs — Ceph Documentation <https://docs.ceph.com/en/latest/rados/operations/add-or-rm-osds/#removing-osds-manual> says "After the OSD has been taken out of the cluster, Ceph begins rebalancing the cluster by migrating placement groups out of the OSD that was removed. " What's the difference between "evacuating PGs" in method 1 and "migrating PGs" in method 2? I think method 1 must read the OSD to be removed. Otherwise, we would not see slow ops warning. Does method 2 not involve reading this OSD? Thanks, Mary On Fri, Apr 26, 2024 at 5:15 AM Eugen Block <eblock@nde.ag> wrote:
Hi,
if you remove the OSD this way, it will be drained. Which means that it will try to recover PGs from this OSD, and in case of hardware failure it might lead to slow requests. It might make sense to forcefully remove the OSD without draining:
- stop the osd daemon - mark it as out - osd purge <id|osd.id> [--force] [--yes-i-really-mean-it]
Regards, Eugen
Zitat von Mary Zhang <maryzhang0920@gmail.com>:
Hi,
We recently removed an osd from our Cepth cluster. Its underlying disk has a hardware issue.
We use command: ceph orch osd rm osd_id --zap
During the process, sometimes ceph cluster enters warning state with slow ops on this osd. Our rgw also failed to respond to requests and returned 503.
We restarted rgw daemon to make it work again. But the same failure occured from time to time. Eventually we noticed that rgw 503 error is a result of osd slow ops.
Our cluster has 18 hosts and 210 OSDs. We expect remove an osd with hardware issue won't impact cluster performance & rgw availbility. Is our expectation reasonable? What's the best way to handle osd with hardware failures?
Thank you in advance for any comments or suggestions.
Best Regards, Mary Zhang _______________________________________________ ceph-users mailing list -- ceph-users@ceph.io To unsubscribe send an email to ceph-users-leave@ceph.io
_______________________________________________ ceph-users mailing list -- ceph-users@ceph.io To unsubscribe send an email to ceph-users-leave@ceph.io