doc: add allow_multimds and fs_name parameter

Add a short description and command example to set the allow_multimds
flag and add a <fs_name> place holder to all 'ceph fs set' commands.

Signed-off-by: Jan Fajerski <jfajerski@suse.com>

diff --git a/doc/cephfs/multimds.rst b/doc/cephfs/multimds.rst
index dd13d927c4b7bfe590b7e451f5d063304060a825..1b4f04c8a17480e5295fef54bbb256b638ee8cf5 100644 (file)
--- a/doc/cephfs/multimds.rst
+++ b/doc/cephfs/multimds.rst
@@ -32,6 +32,12 @@ how many ranks will be created.  The actual number of ranks
 in the filesystem will only be increased if a spare daemon is
 available to take on the new rank. For example, if there is only one MDS daemon running, and max_mds is set to two, no second rank will be created.
 
+Before ``max_mds`` can be increased, the ``allow_multimds`` flag must be set.
+The following command sets this flag for a filesystem instance.
+
+::
+    # ceph fs set <fs_name> cephfs allow_multimds true --yes-i-really-mean-it
+
 Set ``max_mds`` to the desired number of ranks.  In the following examples
 the "fsmap" line of "ceph status" is shown to illustrate the expected
 result of commands.
@@ -40,7 +46,7 @@ result of commands.
 
     # fsmap e5: 1/1/1 up {0=a=up:active}, 2 up:standby
 
-    ceph fs set max_mds 2
+    ceph fs set <fs_name> max_mds 2
 
     # fsmap e8: 2/2/2 up {0=a=up:active,1=c=up:creating}, 1 up:standby
     # fsmap e9: 2/2/2 up {0=a=up:active,1=c=up:active}, 1 up:standby
@@ -74,7 +80,7 @@ having just a single active MDS:
 ::
     
     # fsmap e9: 2/2/2 up {0=a=up:active,1=c=up:active}, 1 up:standby
-    ceph fs set max_mds 1
+    ceph fs set <fs_name> max_mds 1
     # fsmap e10: 2/2/1 up {0=a=up:active,1=c=up:active}, 1 up:standby
 
 Note that we still have two active MDSs: the ranks still exist even though