[SOLVED] CEPH keeps recreating a pool named .mgr

L

Lucian Lazar

Well-Known Member
Apr 23, 2018
31
6
48
42
Romania
ecoit.ro
Hi all, as per title, I have created a new Ceph 7 node cluster and noticed that there was a default pool named ".mgr" there. I deleted that pool and created a new one. After some restarts of the managers and monitors, i saw that the pool ".mgr" was recreated all by itself. Is this intended behavior? Is there a problem deleting the pool .mgr? What is the purpose of it?
Thank you all
 
cheiss said:
Hi,

generally pools starting with a dot are internal pools of Ceph and should never be deleted/modified etc.
See the Ceph documentation on pool names: https://docs.ceph.com/en/latest/rados/operations/pools/#pool-names

The ".mgr" pool is used by Ceph to store internal state, created by the ceph-mgr services. (See https://docs.ceph.com/en/latest/mgr/administrator/#module-pool)
Click to expand...
Thank you, that makes perfect sense. As the cluster is new so no data is yet stored on ceph, deleting the .mgr pool have caused something that can byte me in the long run? The pool .mgr has been recreated automatically but not sure if the previously deleted one will cause issues.
 
Lucian Lazar said:
deleting the .mgr pool have caused something that can byte me in the long run?
Click to expand...
It should not, but no guarantee on that part - but as it was re-created automatically and as the cluster was effectively empty anyway, I personally wouldn't worry much.

In any case, this is a valuable sysadmin lesson - never just randomly delete things just because they are there, especially if you don't know what they are for. ;)

You also might want to set the thread as SOLVED by editing the first post, there is a dropdown near the title field, this helps others find this more easily in the future.
 
You must log in or register to reply here.
Top Bottom