From beae0cf14b463b3bb36bd79b8087bf100fdfbdb2 Mon Sep 17 00:00:00 2001 From: Zac Dover Date: Sat, 9 Aug 2025 15:26:41 +1000 Subject: [PATCH] doc/cephfs: edit troubleshooting.rst Edit the section "Expediting MDS Journal Trim" in doc/cephfs/troubleshooting.rst. Signed-off-by: Zac Dover (cherry picked from commit b627eb4995ef1ea5bd0329915567a620ecd907ac) --- doc/cephfs/troubleshooting.rst | 23 +++++++++++++++-------- 1 file changed, 15 insertions(+), 8 deletions(-) diff --git a/doc/cephfs/troubleshooting.rst b/doc/cephfs/troubleshooting.rst index a2698dc3c5c..fdeb6939871 100644 --- a/doc/cephfs/troubleshooting.rst +++ b/doc/cephfs/troubleshooting.rst @@ -86,6 +86,7 @@ Replay completes when the ``journal_read_pos`` reaches the ``journal_write_pos``. The write position does not change during replay. Track the progression of the read position to compute the expected time to complete. +.. _cephfs_troubleshooting_avoiding_recovery_roadblocks: Avoiding recovery roadblocks ---------------------------- @@ -197,17 +198,23 @@ Do the following when restoring your file system: Expediting MDS journal trim =========================== -If your MDS journal grew too large (maybe your MDS was stuck in up:replay for a -long time!), you will want to have the MDS trim its journal more frequently. -You will know the journal is too large because of ``MDS_HEALTH_TRIM`` warnings. +``MDS_HEALTH_TRIM`` warnings indicate that the MDS journal has grown too large. +When the MDS journal has grown too large, use the ``mds_tick_interval`` tunable +to modify the "MDS tick interval". The "tick" interval drives various upkeep +activities in the MDS, and modifying the interval will decrease the size of the +MDS journal by ensuring that it is trimmed more frequently. -The main tunable available to do this is to modify the MDS tick interval. The -"tick" interval drives several upkeep activities in the MDS. It is strongly -recommended no significant file system load be present when modifying this tick -interval. This setting only affects an MDS in ``up:active``. The MDS does not +Make sure that there is no significant file-system load present when modifying +``mds_tick_interval``. See +:ref:`cephfs_troubleshooting_avoiding_recovery_roadblocks` for ways to reduce +load on the CephFS. + +This setting affects only MDSes in the ``up:active`` state. The MDS does not trim its journal during recovery. -.. code:: bash +Run the following command to modify the ``mds_tick_interval`` tunable: + +.. prompt:: bash # ceph config set mds mds_tick_interval 2 -- 2.39.5