doc: osd-config Add Configuration Options for op queue.

Signed-off-by: Robert LeBlanc <robert.leblanc@endurance.com>

diff --git a/doc/rados/configuration/osd-config-ref.rst b/doc/rados/configuration/osd-config-ref.rst
index 5e6f61ffe89820ec733fe7d580a3a8ac8fc3e0f8..68b140f6aac99114df8cee71281ca6bf53caa0f6 100644 (file)
--- a/doc/rados/configuration/osd-config-ref.rst
+++ b/doc/rados/configuration/osd-config-ref.rst
@@ -331,6 +331,42 @@ recovery operations to ensure optimal performance during recovery.
 :Default: ``2`` 
 
 
+``osd op queue``
+
+:Description: This sets the type of queue to be used for prioritizing ops
+              in the OSDs. Both queues feature a strict sub-queue which is
+              dequeued before the normal queue. The normal queue is different
+              between implementations. The original PrioritizedQueue (``prio``) uses a
+              token bucket system which when there are sufficient tokens will
+              dequeue high priority queues first. If there are not enough
+              tokens available, queues are dequeued low priority to high priority.
+              The new WeightedPriorityQueue (``wpq``) dequeues all priorities in
+              relation to their priorities to prevent starvation of any queue.
+              WPQ should help in cases where a few OSDs are more overloaded
+              than others. Requires a restart.
+
+:Type: String
+:Valid Choices: prio, wpq
+:Default: ``prio``
+
+
+``osd op queue cut off``
+
+:Description: This selects which priority ops will be sent to the strict
+              queue verses the normal queue. The ``low`` setting sends all
+              replication ops and higher to the strict queue, while the ``high``
+              option sends only replication acknowledgement ops and higher to
+              the strict queue. Setting this to ``high`` should help when a few
+              OSDs in the cluster are very busy especially when combined with
+              ``wpq`` in the ``osd op queue`` setting. OSDs that are very busy
+              handling replication traffic could starve primary client traffic
+              on these OSDs without these settings. Requires a restart.
+
+:Type: String
+:Valid Choices: low, high
+:Default: ``low``
+
+
 ``osd client op priority``
 
 :Description: The priority set for client operations. It is relative to