Chapter 10. Updating noautoscale flag

You can also set the target size of a pool at creation time by adding the optional --target-size-bytes <bytes> argument to the ceph osd pool create command.

You can also set the target size of a pool at creation time by adding the optional --target-size-ratio <ratio> argument to the ceph osd pool create command.

To set the number of placement groups in a pool, you must specify the number of placement groups at the time you create the pool. See Creating a Pool for details. Once you set placement groups for a pool, you can increase the number of placement groups (but you cannot decrease the number of placement groups). To increase the number of placement groups, execute the following:

ceph osd pool set POOL_NAME pg_num PG_NUM

ceph osd pool set POOL_NAME pg_num PG_NUM

Once you increase the number of placement groups, you must also increase the number of placement groups for placement (pgp_num) before your cluster will rebalance. The pgp_num should be equal to the pg_num. To increase the number of placement groups for placement, execute the following:

ceph osd pool set POOL_NAME pgp_num PGP_NUM

ceph osd pool set POOL_NAME pgp_num PGP_NUM

To get the number of placement groups in a pool, execute the following:

ceph osd pool get POOL_NAME pg_num

ceph osd pool get POOL_NAME pg_num

To get the statistics for the placement groups in your storag cluster, execute the following:

ceph pg dump [--format FORMAT]

ceph pg dump [--format FORMAT]

Valid formats are plain (default) and json.

To get the statistics for all placement groups stuck in a specified state, execute the following:

ceph pg dump_stuck {inactive|unclean|stale|undersized|degraded [inactive|unclean|stale|undersized|degraded...]} INTERVAL

ceph pg dump_stuck {inactive|unclean|stale|undersized|degraded [inactive|unclean|stale|undersized|degraded...]} INTERVAL

Inactive Placement groups cannot process reads or writes because they are waiting for an OSD with the most up-to-date data to come up and in.

Unclean Placement groups contain objects that are not replicated the desired number of times. They should be recovering.

Stale Placement groups are in an unknown state - the OSDs that host them have not reported to the monitor cluster in a while (configured by mon_osd_report_timeout).

Valid formats are plain (default) and json. The threshold defines the minimum number of seconds the placement group is stuck before including it in the returned statistics (default 300 seconds).

To get the placement group map for a particular placement group, execute the following:

ceph pg map PG_ID

ceph pg map PG_ID

[ceph: root@host01 /]# ceph pg map 1.6c

[ceph: root@host01 /]# ceph pg map 1.6c

Ceph returns the placement group map, the placement group, and the OSD status:

osdmap e13 pg 1.6c (1.6c) -> up [1,0] acting [1,0]

osdmap e13 pg 1.6c (1.6c) -> up [1,0] acting [1,0]

To scrub a placement group, execute the following:

ceph pg scrub PG_ID

ceph pg scrub PG_ID

Ceph checks the primary and any replica nodes, generates a catalog of all objects in the placement group and compares them to ensure that no objects are missing or mismatched, and their contents are consistent. Assuming the replicas all match, a final semantic sweep ensures that all of the snapshot-related object metadata is consistent. Errors are reported via logs.

If the cluster has lost one or more objects, and you have decided to abandon the search for the lost data, you must mark the unfound objects as lost.

If all possible locations have been queried and objects are still lost, you might have to give up on the lost objects. This is possible given unusual combinations of failures that allow the cluster to learn about writes that were performed before the writes themselves are recovered.

Currently the only supported option is "revert", which will either roll back to a previous version of the object or (if it was a new object) forget about it entirely. To mark the "unfound" objects as "lost", execute the following:

ceph pg PG_ID mark_unfound_lost revert|delete

ceph pg PG_ID mark_unfound_lost revert|delete