active + clean
โ
Best possible state.
All replicas of the data are available and fully synchronized across OSDs.
Cause: The system is healthy, all OSDs are online, and replication or erasure coding is working correctly.
active + degraded
๐ธ Data is available, but some replicas are still missing or not yet rebuilt.
Possible causes:
One or more OSDs are down or failed.
Data is still being recovered on other OSDs.
active + recovering
๐ The PG is restoring data from failed OSDs to healthy ones.
Cause:
After an OSD comes back online or a new disk is added, Ceph starts rebuilding replicas.
High load or temporary failures.
active + remapped
๐ฆ The PG has been moved to another location due to changes in the CRUSH map or OSD reallocation.
Possible causes:
Changes in CRUSH rules or OSD weight.
Adding/removing OSDs.
active + backfilling
๐ Similar to recovering, but filling PGs onto a newly added or freed OSD.
Cause: A new OSD was added or CRUSH weights changed, triggering data movement.
active + undersized
โ ๏ธ The number of available replicas is less than the required count.
Possible causes:
Some OSDs are down or out.
Insufficient capacity to host all replicas.
stale
โณ The state is unknown because OSDs holding the PG havenโt reported for a long time.
Possible causes:
Network issues between MONs and OSDs.
OSD daemon is completely down.
peering
๐ The process of synchronizing replicas and selecting the authoritative copy.
Possible causes:
OSD restarts.
CRUSH changes or data movement.
incomplete
โ Ceph could not find a complete or reliable replica.
Data may be lost.
Possible causes:
Too many OSDs are unavailable.
Required quorum for authoritative copy was not reached.
down
๐ซ The PG is fully inactive and no replicas are available.
Possible causes:
All OSDs containing the PG are down.
Disk corruption or severe hardware failure.