doc: document new force-recovery/force-backfill commands

Documentation for new pg force-recovery, pg force-backfill,
pg-cancel-force-recovery and pg-cancel-force-backfill.

Signed-off-by: Piotr Dałek <piotr.dalek@corp.ovh.com>

diff --git a/doc/rados/operations/pg-states.rst b/doc/rados/operations/pg-states.rst
index 233042945046aacde62501dbf805960843847612..0fbd3dcf0b0494bb94154c1e63e4a4c44de87ced 100644 (file)
--- a/doc/rados/operations/pg-states.rst
+++ b/doc/rados/operations/pg-states.rst
@@ -38,11 +38,17 @@ map is ``active + clean``.
 *Recovering*
   Ceph is migrating/synchronizing objects and their replicas.
 
+*Forced-Recovery*
+  High recovery priority of that PG is enforced by user.
+
 *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.
 
+*Forced-Backfill*
+  High backfill priority of that PG is enforced by user.
+
 *Wait-backfill*
   The placement group is waiting in line to start backfill.
 

diff --git a/doc/rados/operations/placement-groups.rst b/doc/rados/operations/placement-groups.rst
index d822373dd168b0317be9063c98bc71bac61c4c60..10979a9c4d75c82394a7423627ff21a6dfa1f249 100644 (file)
--- a/doc/rados/operations/placement-groups.rst
+++ b/doc/rados/operations/placement-groups.rst
@@ -403,6 +403,36 @@ 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.
 
+Prioritize backfill/recovery of a Placement Group(s)
+====================================================
+
+You may run into a situation where a bunch of placement groups will require
+recovery and/or backfill, and some particular groups hold data more important
+than others (for example, those PGs may hold data for images used by running
+machines and other PGs may be used by inactive machines/less relevant data).
+In that case, you may want to prioritize recovery of those groups so
+performance and/or availability of data stored on those groups is restored
+earlier. To do this (mark particular placement group(s) as prioritized during 
+backfill or recovery), execute the following::
+
+        ceph pg force-recovery {pg-id} [{pg-id #2}] [{pg-id #3} ...]
+        ceph pg force-backfill {pg-id} [{pg-id #2}] [{pg-id #3} ...]
+
+This will cause Ceph to perform recovery or backfill on specified placement
+groups first, before other placement groups. This does not interrupt currently
+ongoing backfills or recovery, but causes specified PGs to be processed
+as soon as possible. If you change your mind or prioritize wrong groups,
+use::
+
+        ceph pg cancel-force-recovery {pg-id} [{pg-id #2}] [{pg-id #3} ...]
+        ceph pg cancel-force-backfill {pg-id} [{pg-id #2}] [{pg-id #3} ...]
+
+This will remove "force" flag from those PGs and they will be processed
+in default order. Again, this doesn't affect currently processed placement
+group, only those that are still queued.
+
+The "force" flag is cleared automatically after recovery or backfill of group
+is done.
 
 Revert Lost
 ===========