svn commit: r334446 - projects/pnfs-planb-server/usr.sbin/nfsd

[Rick Macklem]

Author: rmacklem
Date: Thu May 31 21:22:09 2018
New Revision: 334446
URL: https://svnweb.freebsd.org/changeset/base/334446

Log:
  Update nfsd.8 to reflect the recent change to a distributed mirroring model.

Modified:
  projects/pnfs-planb-server/usr.sbin/nfsd/nfsd.8

Modified: projects/pnfs-planb-server/usr.sbin/nfsd/nfsd.8
==============================================================================
--- projects/pnfs-planb-server/usr.sbin/nfsd/nfsd.8	Thu May 31 20:22:47 2018	(r334445)
+++ projects/pnfs-planb-server/usr.sbin/nfsd/nfsd.8	Thu May 31 21:22:09 2018	(r334446)
@@ -28,7 +28,7 @@
 .\"	@(#)nfsd.8	8.4 (Berkeley) 3/29/95
 .\" $FreeBSD$
 .\"
-.Dd April 25, 2015
+.Dd May 31, 2018
 .Dt NFSD 8
 .Os
 .Sh NAME
@@ -42,6 +42,7 @@ server
 .Op Fl n Ar num_servers
 .Op Fl h Ar bindip
 .Op Fl p Ar pnfs_setup
+.Op Fl m Ar mirror_level
 .Op Fl Fl maxthreads Ar max_threads
 .Op Fl Fl minthreads Ar min_threads
 .Sh DESCRIPTION
@@ -114,7 +115,7 @@ as a Data Server (DS) for it to use.
 .Pp
 The
 .Ar pnfs_setup
-string is a set of fields separated by ',' and '#' characters:
+string is a set of fields separated by ',' characters:
 .Bl -tag -width Ds
 Each of these fields specifies one Data Server.
 It consists of a server hostname, followed by a ':'
@@ -131,25 +132,24 @@ Would specify two DS servers called nfsv4-data0 and nf
 the data storage component of the pNFS service.
 The directories "/data0" and "/data1" are where the data storage servers exported
 storage directories are mounted on this system (which will act as the MDS).
+.El
+.It Fl m Ar mirror_level
+This option is only meaningful when used with the
+.Fl p
+option.
+It specifies the ``mirror_level'', which defines how many of the DSs will
+have a copy of a file's data storage file.
+The default of one implies no mirroring of data storage files on the DSs.
+The ``mirror_level'' would normally be set to 2 to enable mirroring, but
+can be as high as NFSDEV_MAXMIRRORS.
 .Pp
-If the fields are separated by the '#' character, it indicates that these
-DSs are to be configured as a mirrored set.
-For example:
-.sp
-nfsv4-data0:/data0#nfsv4-data1:/data1,nfsv4-data2:/data2#nfsv4-data3:/data3
-.sp
-Would specify two mirrored pairs of DSs, with nfsv4-data0 plus nfsv4-data1
-comprising one mirrored pair and nfsv4-data2 plus nfsv4-data3 comprising
-the other mirrored pair.
-.Pp
-If there are mirrored sets of DSs, the server must use the Flexible File
+If mirroring is enabled, the server must use the Flexible File
 layout.
-If there are no mirrored sets of DSs, the server will use the File layout
+If mirroring is not enabled, the server will use the File layout
 by default, but this default can be changed to the Flexible File layout if the
 .Xr sysctl 1
 vfs.nfsd.default_flexfile
 is set non-zero.
-.El
 .It Fl t
 Serve
 .Tn TCP NFS
@@ -288,3 +288,12 @@ you must kill
 and then restart it, after the
 .Xr gssd 8
 is running.
+.Pp
+If mirroring is enabled via the
+.Fl m
+option and there are Linux clients doing NFSv4.1 mounts, those clients
+need to be patched to support the ``tightly coupled'' variant of
+the Flexible File layout or the
+.Xr sysctl 1
+vfs.nfsd.flexlinuxhack
+must be set on the MDS as a workaround.