update sources to v12.1.2

[ceph.git] / ceph / doc / rados / operations / placement-groups.rst

diff --git a/ceph/doc/rados/operations/placement-groups.rst b/ceph/doc/rados/operations/placement-groups.rst
index d822373dd168b0317be9063c98bc71bac61c4c60..fee833ad0c6c32ac5c18a48af4486f0f36d5e63c 100644 (file)
--- a/ceph/doc/rados/operations/placement-groups.rst
+++ b/ceph/doc/rados/operations/placement-groups.rst
@@ -306,7 +306,7 @@ Set the Number of Placement Groups
 
 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 `Create a Pool`_ for details. Once you've set placement groups for a
+See `Create a Pool`_ for details. Once you have set placement groups for a
 pool, you may 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::
@@ -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
 ===========