From b6a97d83da5290cb3cc4e7e6c07dbac5b7ecb7bc Mon Sep 17 00:00:00 2001 From: Loic Dachary Date: Mon, 1 Sep 2014 19:15:57 +0200 Subject: [PATCH] documentation: disk thread ioprio options Signed-off-by: Loic Dachary --- doc/rados/configuration/osd-config-ref.rst | 35 ++++++++++++++++++++++ 1 file changed, 35 insertions(+) diff --git a/doc/rados/configuration/osd-config-ref.rst b/doc/rados/configuration/osd-config-ref.rst index 3ebb861be6ba3..5bc6bc8c81886 100644 --- a/doc/rados/configuration/osd-config-ref.rst +++ b/doc/rados/configuration/osd-config-ref.rst @@ -320,6 +320,41 @@ recovery operations to ensure optimal performance during recovery. :Type: 32-bit Integer :Default: ``1`` +``disk thread ioprio class`` + +:Description: Warning: it will only be used if both ``disk thread + ioprio class`` and ``disk thread ioprio priority`` are + set to a non default value. Sets the ioprio_set(2) I/O + scheduling ``class`` for the disk thread. Acceptable + values are ``idle``, ``be`` or ``rt``. The ``idle`` + class means the disk thread will have lower priority + than any other thread in the OSD. This is useful to slow + down scrubbing on an OSD that is busy handling client + operations. ``be`` is the default and is the same + priority as all other threads in the OSD. ``rt`` means + the disk thread will have precendence over all other + threads in the OSD. This is useful if scrubbing is much + needed and must make progress at the expense of client + operations. Note: Only works with the Linux Kernel CFQ + scheduler. +:Type: String +:Default: the empty string + +``disk thread ioprio priority`` + +:Description: Warning: it will only be used if both ``disk thread + ioprio class`` and ``disk thread ioprio priority`` are + set to a non default value. It sets the ioprio_set(2) + I/O scheduling ``priority`` of the disk thread ranging + from 0 (highest) to 7 (lowest). If all OSDs on a given + host were in class ``idle`` and compete for I/O + (i.e. due to controller congestion), it can be used to + lower the disk thread priority of one OSD to 7 so that + another OSD with priority 0 can potentially scrub + faster. Note: Only works with the Linux Kernel CFQ + scheduler. +:Type: Integer in the range of 0 to 7 or -1 if not to be used. +:Default: ``-1`` ``osd op history size`` -- 2.39.5