+Enforcing minimum version of CephFS client is achieved by setting required
+client features. Commands to manipulate required client features of a file
+system:
+
+::
+
+ fs required_client_features <fs name> add reply_encoding
+ fs required_client_features <fs name> rm reply_encoding
+
+To list all CephFS features
+
+::
+
+ fs feature ls
+
+
+CephFS features and first release they came out.
+
++------------------+--------------+-----------------+
+| Feature | Ceph release | Upstream Kernel |
++==================+==============+=================+
+| jewel | jewel | 4.5 |
++------------------+--------------+-----------------+
+| kraken | kraken | 4.13 |
++------------------+--------------+-----------------+
+| luminous | luminous | 4.13 |
++------------------+--------------+-----------------+
+| mimic | mimic | 4.19 |
++------------------+--------------+-----------------+
+| reply_encoding | nautilus | 5.1 |
++------------------+--------------+-----------------+
+| reclaim_client | nautilus | N/A |
++------------------+--------------+-----------------+
+| lazy_caps_wanted | nautilus | 5.1 |
++------------------+--------------+-----------------+
+| multi_reconnect | nautilus | 5.1 |
++------------------+--------------+-----------------+
+| deleg_ino | octopus | 5.6 |
++------------------+--------------+-----------------+
+| metric_collect | pacific | N/A |
++------------------+--------------+-----------------+
+
+CephFS Feature Descriptions
+
+
+::
+
+ reply_encoding
+
+MDS encodes request reply in extensible format if client supports this feature.
+
+
+::
+
+ reclaim_client
+
+MDS allows new client to reclaim another (dead) client's states. This feature
+is used by NFS-Ganesha.
+
+
+::
+
+ lazy_caps_wanted
+
+When a stale client resumes, if the client supports this feature, mds only needs
+to re-issue caps that are explicitly wanted.
+
+
+::
+
+ multi_reconnect
+
+When mds failover, client sends reconnect messages to mds, to reestablish cache
+states. If MDS supports this feature, client can split large reconnect message
+into multiple ones.
+
+
+::
+
+ deleg_ino
+
+MDS delegate inode numbers to client if client supports this feature. Having
+delegated inode numbers is a prerequisite for client to do async file creation.
+
+
+::
+
+ metric_collect
+
+Clients can send performance metric to MDS if MDS support this feature.
+