On Wed, Mar 12, 2025 at 06:32:09PM +0100, Janne Johansson wrote:
Den ons 12 mars 2025 kl 17:12 skrev Alexander Patrakov <patrakov@gmail.com>:
I need to take 3 of them, 0, 10 and 30, out, is it safe to run out on all 3 OSDs at the same time with "ceph osd out 0 10 20" or do I need to take one after the other out?
It is not safe. [...] What you can do is lower the weight of them to 0.0 and ceph will start move PGs off them into the others, and when they have 0 PGs, you can purge them and stop the OSD process and remove the disk.
Please note that the original post talks about not yanking OSD drives physically, but about running the "ceph osd out" command. This command is exactly equivalent to reweighing the OSD to zero.
Yes, my bad. I misread the "ceph osd out" as "taking out". You are right, telling ceph via "ceph osd out" or reweighting it to zero is the same, and both works to make the cluster start emptying those OSDs.
The reason I asked is that several months back I got a off list reply from a frequent poster on this list, that setting 3 OSDs out at the same time could give me incomplete PGs as a result. But a least now I have 2 saying is OK and 1 saying it's not so thank you Alexander and Janne. -- Kai Stian Olstad