update sources to 12.2.7

[ceph.git] / ceph / doc / cephfs / administration.rst

diff --git a/ceph/doc/cephfs/administration.rst b/ceph/doc/cephfs/administration.rst
index 23bd5fc6a991ed222b42b1b7117166eba01b7be8..71a0e4075d10fb00c5db9255aa8cc22c8d1d6593 100644 (file)
--- a/ceph/doc/cephfs/administration.rst
+++ b/ceph/doc/cephfs/administration.rst
@@ -74,6 +74,22 @@ appear to be eg. exabytes in size, causing load on the MDS as it tries
 to enumerate the objects during operations like stats or deletes.
 
 
 to enumerate the objects during operations like stats or deletes.
 
 

+Taking the cluster down
+-----------------------
+
+Taking a CephFS cluster down is done by reducing the number of ranks to 1,
+setting the cluster_down flag, and then failing the last rank. For example:
+
+::
+    ceph fs set <fs_name> max_mds 1
+    ceph mds deactivate <fs_name>:1 # rank 2 of 2
+    ceph status # wait for rank 1 to finish stopping
+    ceph fs set <fs_name> cluster_down true
+    ceph mds fail <fs_name>:0
+
+Setting the ``cluster_down`` flag prevents standbys from taking over the failed
+rank.
+

 Daemons
 -------
 
 Daemons
 -------
 


@@ -81,16 +97,36 @@ These commands act on specific mds daemons or ranks.
 
 ::
 
 
 ::
 

-    mds fail <gid/name/role
+    mds fail <gid/name/role>
+
+Mark an MDS daemon as failed.  This is equivalent to what the cluster
+would do if an MDS daemon had failed to send a message to the mon
+for ``mds_beacon_grace`` second.  If the daemon was active and a suitable
+standby is available, using ``mds fail`` will force a failover to the standby.
+
+If the MDS daemon was in reality still running, then using ``mds fail``
+will cause the daemon to restart.  If it was active and a standby was
+available, then the "failed" daemon will return as a standby.

 
 

-This command deactivates an MDS causing it to flush its entire journal to
+::
+
+    mds deactivate <role>
+
+Deactivate an MDS, causing it to flush its entire journal to

 backing RADOS objects and close all open client sessions. Deactivating an MDS
 is primarily intended for bringing down a rank after reducing the number of
 backing RADOS objects and close all open client sessions. Deactivating an MDS
 is primarily intended for bringing down a rank after reducing the number of

-active MDS (max_mds).
+active MDS (max_mds). Once the rank is deactivated, the MDS daemon will rejoin the
+cluster as a standby.
+``<role>`` can take one of three forms:

 
 ::
 
 
 ::
 

-    mds deactivate <role>
+    <fs_name>:<rank>
+    <fs_id>:<rank>
+    <rank>
+
+Use ``mds deactivate`` in conjunction with adjustments to ``max_mds`` to
+shrink an MDS cluster.  See :doc:`/cephfs/multimds`

 
 ::
 
 
 ::