On Apr 22, 2026, at 12:04 PM, Jacek Rużyczka via ceph-users <ceph-users@ceph.io> wrote:

Hi Eugen, Hi Frédéric,

One after the other, please:

Do you have the ceph-osd package installed on the servers? It's known

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to be a potential issue when trying to use cephadm while ceph packages are installed (except for cephadm, of course, and maybe ceph-common).

My understanding is that the orchestrator uses a different copy of cephadm than what the package installs, in order to avoid conflicts. Issues with `ceph-osd` installed are problematic, though, as that's neeed to get ceph-bluestore-tool. Is there a tracker for this?

And just one thought on the number of monitors: It's not useful to

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have 4 MONs, an odd number is recommended. With 4 MONs you'd still lose quorum when two MONs go down, so it doesn't offer any more resiliency than 3 MONs.

Shall I reduce it to 3?

If you have at least 5 hosts, I would increase to 5.