-The Lustre filesystem this service will be part of. The maximum filesystem_name
-length is 8 characters. Required for all targets other than MGS.
+The Lustre filesystem this target will be part of. Valid
+.IR filesystem_name s
+are between 1 and 8 characters long and must only use upper- and lower-case
+English letters, numbers, and '\-', or '_' (regexp [-_a\-zA\-Z0\-9]). All
+targets in a single filesystem must specify the same
+.IR filesystem_name ,
+and it must be unique between all filesystems mounted by a single client
+at one time. Using "lustre" as the filesystem name is discouraged, to avoid
+future problems if a client needs to mount two such filesystems, and to
+reduce confusion for administrators/users between "lustre" as the
+.I filesystem_name
+and "lustre" as the literal string that must be used in places for the
+.BR filesystem_type .
+The
+.B \--fsname
+option is not valid for the MGS, since it may be used for multiple filesystems.