No, the data is not inaccessible until you wipe the OSDs.
Ah, that's good to know that at least the data are still there. How many OSDs are we talking about here? I've got 4 OSDs, which hold 1.3 TB of data in total. I do have a backup of them on an external HDD, which spit out a handful of warnings during the last restore, so destroying the previous SSD, creating new ones, and trying another restore are things I'd like to avoid. And regarding the fsid, you can specify it in the bootstrap command,
you won’t be able to change it afterwards.
This is exactly what I tried to do: sudo cephadm bootstrap --mon-ip $MYIP --config /etc/ceph/ceph.conf~~ --allow-overwrite And /etc/ceph/ceph.conf~~ contains the old FSID: # minimal ceph.conf for 8aad3073-39a1-11f1-bf6e-f2704a1efa9b [global] fsid = 8aad3073-39a1-11f1-bf6e-f2704a1efa9b mon_host = [v2:10.20.0.11:3300/0,v1:10.20.0.11:6789/0] [v2: 10.20.0.12:3300/0,v1:10.20.0.12:6789/0] [v2: 10.20.0.13:3300/0,v1:10.20.0.13:6789/0] [v2: 10.20.0.14:3300/0,v1:10.20.0.14:6789/0] Nevertheless, cephadm ignored the old settings and gave the new cluster a generated ID. So I've gotta tear down the cluster and start again? What about the key pairs stored in /etc/ceph? You can simply create the OSD directories and create a symbolic link to
the block device. Cephadm simply maps it then.
I've now recreated the dir /var/lib/ceph/osd/ceph-2 and have to symlink /dev/ceph-81bc1761-e8f6-446c-96f3-eb1b8f92628b/o sd-block-9f7fd40d-0698-40b9-8718-62942b03e263 there? Or should ceph-2 be the name of the symlink? I recommend to hire a professional to help you out, just to be on the safe
side.
I've got a Ceph expert in our hackspace, but I'm not sure whether he can help me.