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.
This commit is contained in:
Rick Macklem 2018-07-02 19:33:26 +00:00
parent ed46427268
commit 0479387e0a
Notes: svn2git 2020-12-20 02:59:44 +00:00
svn path=/head/; revision=335872

View File

@ -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.