*down*
A replica with necessary data is down, so the placement group is offline.
+*laggy*
+ A replica is not acknowledging new leases from the primary in a timely fashion; IO is temporarily paused.
+
+*wait*
+ The set of OSDs for this PG has just changed and IO is temporarily paused until the previous interval's leases expire.
+
*scrubbing*
Ceph is checking the placement group metadata for inconsistencies.