From 2cf1e713cec59c989602c001e710ba499005ab04 Mon Sep 17 00:00:00 2001 From: Sridhar Seshasayee Date: Thu, 4 Jun 2026 12:28:35 +0530 Subject: [PATCH] doc/rados/configuration: Remove wpq recommendation warning for EC clusters Remove the warning that recommends using wpq scheduler as a fallback for EC clusters. This issue is addressed by considering EC recovery reads as background, assigning an accurate cost for those reads and tuning the QoS parameters associated with best-effort class of operations. Signed-off-by: Sridhar Seshasayee --- doc/rados/configuration/mclock-config-ref.rst | 16 ---------------- 1 file changed, 16 deletions(-) diff --git a/doc/rados/configuration/mclock-config-ref.rst b/doc/rados/configuration/mclock-config-ref.rst index 316e1faa5e1..fc5201b32fc 100644 --- a/doc/rados/configuration/mclock-config-ref.rst +++ b/doc/rados/configuration/mclock-config-ref.rst @@ -4,22 +4,6 @@ .. index:: mclock; configuration -.. warning:: On large clusters with erasure-coded pools, operators may - observe slow ops during recovery or backfill (for example, when an - OSD is drained out). Under mClock, EC sub-operation reads issued - during recovery are currently routed through the ``immediate`` - high-priority queue and bypass mClock throttling. When many OSDs - read concurrently from a single source OSD, this can saturate that - OSD's high-priority queue and starve client and background work. - As an interim measure, such deployments are advised to switch to - the ``WeightedPriorityQueue`` (``wpq``) scheduler. The change can - be applied cluster-wide and takes effect after each OSD is - restarted: - - .. prompt:: bash # - - ceph config set osd osd_op_queue wpq - QoS support in Ceph is implemented using a queuing scheduler based on `the dmClock algorithm`_. See :ref:`dmclock-qos` section for more details. -- 2.47.3