From 0479387e0ae72132bd249ae4b334d298275f06fa Mon Sep 17 00:00:00 2001
From: Rick Macklem <rmacklem@FreeBSD.org>
Date: Mon, 2 Jul 2018 19:33:26 +0000
Subject: [PATCH] Document the "#mds_path" suffix for the "-p" command line
 option.

r335871 added support for an optional suffix of "#mds_path" that can be
applied to each entry in the "-p" option argument. This specifies that
the DS should be used to store files for the file system on the MDS
at "mds_path".
This patch documents this optional suffix.

This is a content change.
---
 usr.sbin/nfsd/nfsd.8 | 34 ++++++++++++++++++++++++++++++++--
 1 file changed, 32 insertions(+), 2 deletions(-)

diff --git a/usr.sbin/nfsd/nfsd.8 b/usr.sbin/nfsd/nfsd.8
index e139dc0d6c51..d2b993ee38d5 100644
--- a/usr.sbin/nfsd/nfsd.8
+++ b/usr.sbin/nfsd/nfsd.8
@@ -28,7 +28,7 @@
 .\"	@(#)nfsd.8	8.4 (Berkeley) 3/29/95
 .\" $FreeBSD$
 .\"
-.Dd May 31, 2018
+.Dd June 30, 2018
 .Dt NFSD 8
 .Os
 .Sh NAME
@@ -126,21 +126,40 @@ so the
 .Dq server hostname
 must resolve to an IPv4 address and support mounts on that address.
 This needs to be extended to support IPv6 addresses in the near future.
+This can optionally be followed by a '#' and the mds_path, which is the
+directory path for an exported file system on this MDS.
+If this is specified, it means that this DS is to be used to store data
+files for this mds_path file system only.
+If this optional component does not exist, the DS will be used to store data
+files for all exported MDS file systems.
 The DS storage file systems must be mounted on this system before the
 .Nm
 is started with this option specified.
+.br
 For example:
 .sp
 nfsv4-data0:/data0,nfsv4-data1:/data1
 .sp
-Would specify two DS servers called nfsv4-data0 and nfsv4-data1 that comprise
+would specify two DS servers called nfsv4-data0 and nfsv4-data1 that comprise
 the data storage component of the pNFS service.
+These two DSs would be used to store data files for all exported file systems
+on this MDS.
 The directories
 .Dq /data0
 and
 .Dq /data1
 are where the data storage servers exported
 storage directories are mounted on this system (which will act as the MDS).
+.br
+Whereas, for the example:
+.sp
+nfsv4-data0:/data0#/export1,nfsv4-data1:/data1#/export2
+.sp
+would specify two DSs as above, however nfsv4-data0 will be used to store
+data files for
+.Dq /export1
+and nfsv4-data1 will be used to store data files for
+.Dq /export2 .
 .El
 .It Fl m Ar mirror_level
 This option is only meaningful when used with the
@@ -155,6 +174,17 @@ The
 .Dq mirror_level
 would normally be set to 2 to enable mirroring, but
 can be as high as NFSDEV_MAXMIRRORS.
+There must be at least
+.Dq mirror_level
+DSs for each exported file system on the MDS, as specified in the
+.Fl p
+option.
+This implies that, for the above example using "#/export1" and "#/export2",
+mirroring cannot be done.
+There would need to be two DS entries for each of "#/export1" and "#/export2"
+in order to support a
+.Dq mirror_level
+of two.
 .Pp
 If mirroring is enabled, the server must use the Flexible File
 layout.