doc/cephfs: link section for pausing async threads in section for...

disabling volumes plugin part.

Fixes: https://tracker.ceph.com/issues/70479
Signed-off-by: Rishabh Dave <ridave@redhat.com>
(cherry picked from commit 36cfbfb0eacbfbd459558d1bdff699daf8fae575)

diff --git a/doc/cephfs/fs-volumes.rst b/doc/cephfs/fs-volumes.rst
index baa6f5923f89a8b08f2c6d90e11d2c0068db2b41..f169ea533dd403451b406707df8674c05ee7293a 100644 (file)
--- a/doc/cephfs/fs-volumes.rst
+++ b/doc/cephfs/fs-volumes.rst
@@ -906,7 +906,8 @@ services on the Ceph cluster accessed through this plugin.
 Before resorting to a measure as drastic as this, it is a good idea to try less
 drastic measures and then assess if the file system experience has improved due
 to it. One example of such less drastic measure is to disable asynchronous
-threads launched by volumes plugins for cloning and purging trash.
+threads launched by volumes plugins for cloning and purging trash. For details
+on these see: :ref:`pause-purge-threads` and :ref:`pause-clone-threads`.
 
 
 .. _manila: https://github.com/openstack/manila

diff --git a/doc/cephfs/troubleshooting.rst b/doc/cephfs/troubleshooting.rst
index 62dd3561c47d60fe107dbda9505aedb4c90d91fd..9531f0a4a09de56c0156432e0d7a86566766ff08 100644 (file)
--- a/doc/cephfs/troubleshooting.rst
+++ b/doc/cephfs/troubleshooting.rst
@@ -128,6 +128,38 @@ things to do:
 
   That prevents any clients from establishing new sessions with the MDS.
 
+* **Dont tweak max_mds** Modifying the FS setting variable ``max_mds`` is
+  sometimes perceived as a good step during troubleshooting or recovery effort.
+  Instead, doing so might further destabilize the cluster. If ``max_mds`` must
+  be changed in such circumstances, run the command to change ``max_mds`` with
+  the confirmation flag (``--yes-i-really-mean-it``)
+
+.. _pause-purge-threads:
+* **Turn off async purge threads** The volumes plugin spawns threads for
+  asynchronously purging trashed/deleted subvolumes. To help troubleshooting or
+  recovery effort, these purge threads can be disabled using:
+
+.. code:: bash
+
+    ceph config set mgr mgr/volumes/pause_purging true
+
+  To resume purging run::
+
+    ceph config set mgr mgr/volumes/pause_purging false
+
+.. _pause-clone-threads:
+* **Turn off async cloner threads** The volumes plugin spawns threads for
+  asynchronously cloning subvolume snapshots. To help troubleshooting or
+  recovery effort, these cloner threads can be disabled using:
+
+.. code:: bash
+
+    ceph config set mgr mgr/volumes/pause_cloning true
+
+  To resume cloning run::
+
+    ceph config set mgr mgr/volumes/pause_cloning false
+
 
 
 Expediting MDS journal trim