Dear ceph users, On one of our clusters I have some difficulties with the upmap balancer. We started with a reasonably well balanced cluster (using the balancer in upmap mode). After a node failure, we crush reweighted all the OSDs of the node to take it out of the cluster - and waited for the cluster to rebalance. Obviously, this significantly changes the crush map - hence the nice balance created by the balancer was gone. The recovery mostly completed - but some of the OSDs became too full - so we neded up with a few PGs that were backfill_toofull. The cluster has plenty of space (overall perhaps 65% full), only a few OSDs are >90% (we have backfillfull_ratio at 92%). The balancer refuses to change anything since the cluster is not clean. Yet - the cluster can't become clean without a few upmaps to help the top 3 or 4 most full OSDs. I would think this is a fairly common situation - trying to recover after some failure. Are there any recommendations on how to proceed? Obviously I can manually find and insert upmaps - but for a large cluster with tens of thousands of PGs, that isn't too practical. Is there a way to tell the balancer to still do something even though some PGs are undersized (with a quick look at the python module - I didn't see any)? The cluster is on Nautilus 14.2.15. Thanks, Andras