doc/cephfs: add note to isolate metadata pool osds

Signed-off-by: Patrick Donnelly <pdonnell@redhat.com>

diff --git a/doc/cephfs/createfs.rst b/doc/cephfs/createfs.rst
index 59706d1d2dc8c503b73931eee0dd4296c299ca2c..4a282e562fe3c79c41e461bdec60c9db86093045 100644 (file)
--- a/doc/cephfs/createfs.rst
+++ b/doc/cephfs/createfs.rst
@@ -15,6 +15,10 @@ There are important considerations when planning these pools:
 - We recommend the fastest feasible low-latency storage devices (NVMe, Optane,
   or at the very least SAS/SATA SSD) for the metadata pool, as this will
   directly affect the latency of client file system operations.
+- We strongly suggest that the CephFS metadata pool be provisioned on dedicated
+  SSD / NVMe OSDs. This ensures that high client workload does not adversely
+  impact metadata operations. See :ref:`device_classes` to configure pools this
+  way.
 - The data pool used to create the file system is the "default" data pool and
   the location for storing all inode backtrace information, which is used for hard link
   management and disaster recovery. For this reason, all CephFS inodes

diff --git a/doc/rados/operations/crush-map.rst b/doc/rados/operations/crush-map.rst
index ac4f1cb12a1beceeaf46a459284a071465d231a7..54ad63130cbc192994f6c49d97701f6d9a74ef2b 100644 (file)
--- a/doc/rados/operations/crush-map.rst
+++ b/doc/rados/operations/crush-map.rst
@@ -221,6 +221,8 @@ To view the contents of the rules, run the following command:
 
    ceph osd crush rule dump
 
+.. _device_classes:
+
 Device classes
 --------------