ceph-volume: docs for --crush-device-class

Signed-off-by: Andrew Schoen <aschoen@redhat.com>
(cherry picked from commit 21f459437bd1208812504a20e5a50f7a47bfa979)

diff --git a/doc/ceph-volume/lvm/prepare.rst b/doc/ceph-volume/lvm/prepare.rst
index 27ebb55d7e6283c0549c9c2af5f41edee28e8221..21d82d35d7305c5a88ec4f1019ee4e0f6cd5d2d1 100644 (file)
--- a/doc/ceph-volume/lvm/prepare.rst
+++ b/doc/ceph-volume/lvm/prepare.rst
@@ -186,6 +186,15 @@ a volume group and a logical volume using the following convention:
 * logical volume name: ``osd-block-{osd_fsid}``
 
 
+Crush device class
+------------------
+
+To set the crush device class for the OSD, use the ``--crush-device-class`` flag. This will
+work for both bluestore and filestore OSDs::
+
+    ceph-volume lvm prepare --bluestore --data vg/lv --crush-device-class foo
+
+
 Storing metadata
 ----------------
 The following tags will get applied as part of the preparation process
@@ -195,6 +204,7 @@ regardless of the type of volume (journal or data) or OSD objectstore:
 * ``encrypted``
 * ``osd_fsid``
 * ``osd_id``
+* ``crush_device_class``
 
 For :term:`filestore` these tags will be added: