This turned out to be really easy to fix. 1. Find the correct number of extents that would fit on the physical devices. In my case 13262 2. Just extend the DB LVMs accordingly (in my case, it was all of them, identically): find /dev/ceph-*/osd-db-* | xargs -I{} lvextend -l 13626 {} 3. Restart the OSDs and they seem to automagically expand the bluefs DB part: Dec 13 20:23:11 mimer-osd14 ceph-5406fed0-d52b-11ec-beff-7ed30a54847b-osd-547[3004851]: debug 2023-12-13T19:23:11.723+0000 7f5126e01200 1 bluefs add_block_device bdev 1 path /var/lib/ceph/osd/ceph-547/block.db size 53 GiB reporting 53GB instead of the 17GB I had before. I would recommend anyone with multiple drives used for block_db to double check their LVM sizes. Best regards, Mikael On Wed, Dec 13, 2023 at 2:37 PM Mikael Öhman <micketeer@gmail.com> wrote:

Hi

Our hosts have 3 NVMEs and 48 spinning drives each. We found that ceph orch made the default lvm size for the block_db 1/3 the total size of the NVMEs. I suspect that ceph only considered one of the NVMEs when determining the size, based the closely related issue; https://tracker.ceph.com/issues/54541

We started having some bluefs spillover events now, so I'm looking for a way to fix this.

Best idea I have so far is to manually specify the "block_db_size" in the osd_spec, then just recreating the entire block_db. Though I'm not sure if that means we'll hit the same issue https://tracker.ceph.com/issues/54541 instead. There would also be a lot of data to move in order to do this to a total of 588 OSD's. Maybe there is a way to just maybe remove and re-add (bigger) block_db?

I would appreciate any suggestions or tips.

Best regards, Mikael