From c08339c9815b80d014cd2b28ae0798b9d77fd54e Mon Sep 17 00:00:00 2001 From: Rishabh Dave Date: Fri, 14 Mar 2025 18:09:56 +0530 Subject: [PATCH] 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 (cherry picked from commit 36cfbfb0eacbfbd459558d1bdff699daf8fae575) --- doc/cephfs/fs-volumes.rst | 3 ++- doc/cephfs/troubleshooting.rst | 31 +++++++++++++++++++++++++++++++ 2 files changed, 33 insertions(+), 1 deletion(-) diff --git a/doc/cephfs/fs-volumes.rst b/doc/cephfs/fs-volumes.rst index b745252f1ea65..04220ecb717f5 100644 --- a/doc/cephfs/fs-volumes.rst +++ b/doc/cephfs/fs-volumes.rst @@ -1554,7 +1554,8 @@ 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 c5c956cf66766..e96fe2454e857 100644 --- a/doc/cephfs/troubleshooting.rst +++ b/doc/cephfs/troubleshooting.rst @@ -128,6 +128,37 @@ 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 -- 2.47.3