Yes, it's expected.  The crush map contains the inputs to the CRUSH hashing
algorithm.  Every change made to the crush map causes the hashing algorithm
to behave slightly differently.  It is consistent though.  If you removed
the new bucket, it would go back to the way it was before you made the
change.

The Ceph team is working to reduce this, but it's unlikely to go away
completely.


On Sun, Apr 5, 2015 at 11:45 AM, Andrey Korolyov <[email protected]> wrote:

> Hello,
>
> after reaching certain ceiling of host/PG ratio, moving empty bucket
> in causes a small rebalance:
>
> ceph osd crush add-bucket 10.10.2.13
> ceph osd crush move 10.10.2.13 root=default rack=unknownrack
>
> I have two pools, one is very large and it is keeping up with proper
> amount of pg/osd but another one contains in fact lesser amount of PGs
> than the number of active OSDs and after insertion of empty bucket in
> it goes to a rebalance, though that the actual placement map is not
> changed. Keeping in mind that this case is very far from being
> offensive to any kind of a sane production configuration, is this an
> expected behavior?
>
> Thanks!
> _______________________________________________
> ceph-users mailing list
> [email protected]
> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
>
_______________________________________________
ceph-users mailing list
[email protected]
http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com

Reply via email to