From 20e556b6240b3dc90cb93b9fd9271edb966ea084 Mon Sep 17 00:00:00 2001 From: Alfredo Deza Date: Tue, 24 Jul 2018 14:39:59 -0400 Subject: [PATCH] doc/bluestore detail the different sizing strategies for block.db based on cluster workload Signed-off-by: Alfredo Deza --- .../configuration/bluestore-config-ref.rst | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/doc/rados/configuration/bluestore-config-ref.rst b/doc/rados/configuration/bluestore-config-ref.rst index a272666aad183..ad07f8b33d7a5 100644 --- a/doc/rados/configuration/bluestore-config-ref.rst +++ b/doc/rados/configuration/bluestore-config-ref.rst @@ -57,6 +57,8 @@ Although there are multiple ways to deploy a Bluestore OSD (unlike Filestore which had 1) here are two common use cases that should help clarify the initial deployment strategy: +.. _bluestore-single-type-device-config: + **block (data) only** ^^^^^^^^^^^^^^^^^^^^^ If all the devices are the same type, for example all are spinning drives, and @@ -72,6 +74,7 @@ of the device), then the :ref:`ceph-volume-lvm` call for an lv named ceph-volume lvm create --bluestore --data ceph-vg/block-lv +.. _bluestore-mixed-device-config: **block and block.db** ^^^^^^^^^^^^^^^^^^^^^^ @@ -117,6 +120,20 @@ These operations should end up creating 4 OSDs, with ``block`` on the slower spinning drives and a 50GB logical volume for each coming from the solid state drive. +Sizing +====== +When using a :ref:`mixed spinning and solid drive setup +` it is important to make a large-enough +``block.db`` logical volume for Bluestore. Generally, ``block.db`` should have +*as large as possible* logical volumes. + +It is recommended that the ``block.db`` size isn't smaller than 4% of +``block``. For example, if the ``block`` size is 1TB, then ``block.db`` +shouldn't be less than 40GB. + +If *not* using a mix of fast and slow devices, it isn't required to create +separate logical volumes for ``block.db`` (or ``block.wal``). Bluestore will +automatically manage these within the space of ``block``. Cache size ========== -- 2.39.5