+.B mkdir <--index|-i mdt_index> <dir>
+Allocate a new directory on a specified MDT.
+
+The "lfs mkdir" command is only executable by root unless
+"mdt.*.enable_remote_dir_gid" is set via "lctl set_param" to be either a
+non-zero GID to limit it to a single group (e.g. "operator" or "admin"),
+or "-1" to allow any group to create remote directories.
+
+The root of the file system is on MDT0000, and directories and files inherit the
+MDT of their parent directory unless a different MDT is specified with this
+command.
+
+By default, only directories on MDT0000 can contain directories that are not on
+the same MDT. However, if "mdt.*.enable_remote_dir" is set non-zero on an MDT
+then it will allow creating remote directories that have parents other than
+MDT0000. This is restricted to avoid creating directory trees that have
+intermediate path components on a series different MDTs and become unavailable
+if any of the intermediate MDTs are offline.
+.TP