Ceph Maintenance
Auto-Recovery
Ceph's natural behaviour is to attempt to ensure redundancy of data across available nodes in the even of OSD or node loss.
Maintenance Options
Ceph can be put into a maintenance mode to not follow this behaviour if a node in the cluster needs some maintenance.
| Flag | Description |
|---|---|
noout |
Prevents OSDs being marked as out of the cluster when they go down, which stops automatic rebalancing |
nobackfill |
Pause backfill operations |
norecover |
Pause all data recovery operations |
Apply these flags with the ceph osd set command
ceph osd set noout
ceph osd set nobackfill
ceph osd set norecover
Redundancy
It is important to take into consideration the redundancy of the cluster. Multiple nodes in a cluster may not be taken into maintenance at one time if the resiliency is only configured on a node level.
OSDs going into readonly?
Unset maintenance flags