Unclean placement groups

Understand and troubleshoot unclean placement groups (PGs).

The ceph health command returns an error message similar to the following example:
HEALTH_WARN 197 pgs stuck unclean

What this means

Ceph marks a placement group as unclean if it has not achieved the active+clean state for the number of seconds specified in the mon_pg_stuck_threshold parameter in the Ceph configuration file. The default value of mon_pg_stuck_threshold is 300 seconds.

If a placement group is unclean, it contains objects that are not replicated the number of times specified in the osd_pool_default_size parameter. The default value of osd_pool_default_size is 3, which means that Ceph creates three replicas.

Usually, unclean placement groups indicate that some OSDs might be down.

For more information, see Listing placement groups stuck in stale inactive or unclean state.

Troubleshooting this problem

  1. Use the ceph osd tree command to determine which OSDs are in a down state.
    For example,
    [ceph: root@host01 /]# ceph osd tree
  2. Troubleshoot and fix any problems with the OSDs. For more information, see Down OSDs.