Hello, I posted this on the Reddit sub, but it was suggested I might get better responses here. I am running a 5-node Ceph cluster (v18.2.2) installed using "cephadm". I am trying to migrate the DB/WAL on our slower HDDs to NVME; I am following this article: https://docs.clyso.com/blog/ceph-volume-create-wal-db-on-separate-device-for... I have a 1TB NVME in each node, and there are four HDDs. I have created the VG ("cephdbX", where "X" is the node number) and four equal-sized LVs ("cephdb1", "cephdb2", "cephdb3", "cephdb4"). On the node I am trying to move the DB/WAL first, I have stopped the systemd OSD service for the OSD I am doing this first to. I have switched into the cephadm shell so I can run the ceph-volume commands, but when I run: ceph-volume lvm new-db --osd-id 10 --osd-fsid 474264fe-b00e-11ee-b586-ac1f6b0ff21a --target cephdb03/cephdb1 I get the following error: --> Target path cephdb03/cephdb1 is not a Logical Volume Unable to attach new volume : cephdb03/cephdb1 If I run 'lvs' in the cephadm shell, I can see the LVs (sorry about the formatting; hopefully you can view it in a way that it isn't a big "jumble"): LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert osd-block-f85a57a8-e2f5-4bda-bc3b-e99d8b70768b ceph-341561e6-da91-4678-b6c8-0f0281443945 -wi-ao---- <1.75t osd-block-f1fd3d53-4ed9-4492-82a0-4686231d57e1 ceph-65ebde73-28ac-4dac-b0cb-4cf8df18bd4b -wi-ao---- 16.37t osd-block-3571394c-3afa-4177-904a-17550f8e902c ceph-6c8de2ed-cae3-4dd9-9ea8-49c94b746878 -wi-a----- 16.37t osd-block-41d44327-3df7-4166-a675-d9630bde4867 ceph-703962c7-6f28-4d8b-b77f-a6eba39da6b2 -wi-ao---- <1.75t osd-block-438c7681-ee6b-4d29-91f5-d487377c3ac9 ceph-71cc35c4-436d-42b7-a704-b21c2d22b43b -wi-ao---- 16.37t osd-block-2ebf78e8-1de1-464e-9125-14a8b7e6796f ceph-7c1fe149-8500-4a41-9052-64f27b2cb70b -wi-ao---- <1.75t osd-block-ca347144-eb84-4e9f-bfb5-81d60659f417 ceph-92595dfe-dc70-47c7-bcab-65b26d84448c -wi-ao---- 16.37t osd-block-2d338a42-83ce-4281-9762-b268e74f83b3 ceph-e9b51fa2-2be1-40f3-b96d-fb0844740afa -wi-ao---- <1.75t cephdb1 cephdb03 -wi-a----- 232.00g cephdb2 cephdb03 -wi-a----- 232.00g cephdb3 cephdb03 -wi-a----- 232.00g cephdb4 cephdb03 -wi-a----- 232.00g lv_root cephnode03-20240110 -wi-ao---- <468.36g lv_swap cephnode03-20240110 -wi-ao---- <7.63g All the official docs I read about it seem to assume the Ceph components are installed directly on the host, rather than in containers (which is what 'cephadm' does) Any advice for migrating the DB/WAL to the SSDs when using 'cephadm'? (I could probably destroy the OSD and manually re-create it with the options for pointing the DB/WAL to the SSD, but I would rather do it without forcing a data migration, otherwise I would have to wait for that with each OSD I am migrating) Followup question: if I do seem to have to go the route of destroying the OSD and re-creating it with the flags for point the DB/WAL to the SSD partition, the syntax I have seen is this: ceph-volume lvm prepare --bluestore --block.db --block.wal --data VOLUME_GROUP/LOGICAL_VOLUME but the above command seems to only specify the location for the data? Should the syntax be more like: ceph-volume lvm prepare --bluestore --block.db VG2/LV1 --block.wal VG2/LV1 --data /dev/sda (assuming my HDD is /dev/sda)? Thanks! :-)