Hello, Ceph users, I would like to use my secondary Ceph cluster for backing up RBD OpenNebula volumes from my primary cluster using mirroring in image+snapshot mode. Because it is for backups only, not a cold-standby, I would like to use erasure coding on the secondary side to save a disk space. Is it supported at all? I tried to create a pool: secondary# ceph osd pool create one-mirror erasure k6m2 secondary# ceph osd pool set one-mirror allow_ec_overwrites true set pool 13 allow_ec_overwrites to true secondary# rbd mirror pool enable --site-name secondary one-mirror image 2024-02-02T11:00:34.123+0100 7f95070ad5c0 -1 librbd::api::Mirror: mode_set: failed to allocate mirroring uuid: (95) Operation not supported When I created a replicated pool instead, this step worked: secondary# ceph osd pool create one-mirror-repl replicated secondary# rbd mirror pool enable --site-name secondary one-mirror-repl image secondary# So, is RBD mirroring supported with erasure-coded pools at all? Thanks! -Yenya -- | Jan "Yenya" Kasprzak <kas at {fi.muni.cz - work | yenya.net - private}> | | https://www.fi.muni.cz/~kas/ GPG: 4096R/A45477D5 | We all agree on the necessity of compromise. We just can't agree on when it's necessary to compromise. --Larry Wall