Placement Group States
When checking a cluster’s status (e.g., running ceph -w or ceph -s),
Ceph will report on the status of the placement groups. A placement group has
one or more states. The optimum state for placement groups in the placement group
map is active + clean.
- Creating
- Ceph is still creating the placement group.
- Active
- Ceph will process requests to the placement group.
- Clean
- Ceph replicated all objects in the placement group the correct number of times.
- Down
- A replica with necessary data is down, so the placement group is offline.
- Replay
- The placement group is waiting for clients to replay operations after an OSD crashed.
- Splitting
- Ceph is splitting the placment group into multiple placement groups. (functional?)
- Scrubbing
- Ceph is checking the placement group for inconsistencies.
- Degraded
- Ceph has not replicated some objects in the placement group the correct number of times yet.
- Inconsistent
- Ceph detects inconsistencies in the one or more replicas of an object in the placement group
(e.g. objects are the wrong size, objects are missing from one replica after recovery finished, etc.).
- Peering
- The placement group is undergoing the peering process
- Repair
- Ceph is checking the placement group and repairing any inconsistencies it finds (if possible).
- Recovering
- Ceph is migrating/synchronizing objects and their replicas.
- Backfill
- Ceph is scanning and synchronizing the entire contents of a placement group
instead of inferring what contents need to be synchronized from the logs of
recent operations. Backfill is a special case of recovery.
- Wait-backfill
- The placement group is waiting in line to start backfill.
- Backfill-toofull
- A backfill operation is waiting because the destination OSD is over its
full ratio.
- Incomplete
- Ceph detects that a placement group is missing a necessary period of history
from its log. If you see this state, report a bug, and try to start any
failed OSDs that may contain the needed information.
- Stale
- The placement group is in an unknown state - the monitors have not received
an update for it since the placement group mapping changed.
- Remapped
- The placement group is temporarily mapped to a different set of OSDs from what
CRUSH specified.