freebsd-skq/usr.sbin/pnfsdsfile/pnfsdsfile.8

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.Dd June 30, 2018
.Dt PNFSDSFILE 8
.Os
.Sh NAME
.Nm pnfsdsfile
.Nd display
a pNFS data storage file's location(s) and/or modify the
.Dq pnfsd.dsfile
extended attribute for them
.Sh SYNOPSIS
.Nm
.Op Fl qz
.Op Fl s Ar dshostname
.Op Fl c Ar old-dshostname,new-dshostname
.Op Fl m Ar mirror_level
.Op Fl r Ar dshostname
.Ar mdsfile
.Sh DESCRIPTION
The
.Nm
command displays the data storage file's location(s) for a pNFS service and/or
modifies the
.Dq pnfsd.dsfile
extended attribute on the
.Ar mdsfile .
A pNFS service maintains a data storage file for each regular file on
the MetaData Server (MDS) on one or more of the Data Servers (DS).
If mirroring is enabled, the data storage file will be on more that one of the DSs.
Unless command options are specified, this command displays the location(s)
of the data storage file for the MDS file
.Ar mdsfile .
It must be used on the MDS and the
.Ar mdsfile
must be a file on the exported local file system and not an NFSv4.1 mount.
This information is stored in the
.Dq pnfsd.dsfile
extended attribute for this
.Ar mdsfile .
The command line options allow the information in the
.Dq pnfsd.dsfile
extended attribute to be changed.
.Pp
The following options are available:
.Bl -tag -width Ds
.It Fl q
This option suppresses printing of the DS file's location(s).
.It Fl z
This option specifies that the file handle field of the pnfsd.dsfile
extended attribute is to filled with all zero bits.
This forces the pNFS MDS to do a Lookup RPC against the DS to acquire the file
handle to update it.
Normally this will only be necessary after the DS file has been recovered
from a backup, causing the file handle to change.
.It Fl s Ar dshostname
This option can be used with
.Fl z
so that the zeroing out of the file handle is only done if the DS server
is the one specified by this option.
.It Fl c Ar old-dshostname,new-dshostname
This option allows a sysadmin to replace the host IP# for the DS in the
pnfsd.dsfile extended attribute.
The old-hostname must resolve to the IP# already in the pnfsd.dsfile extended
attribute or the replacement will not be done.
If the old-dshostname matches, then the IP# is replaced by the first AF_INET
or AF_INET6 address that
.Xr getaddrinfo 3
returns for the new-dshostname.
Changing a DS server's host IP# should be avoided, but this option will
allow it to be changed, if the change is unavoidable.
.It Fl m Ar mirror_level
This option adds entrie(s) to the extended attributes with IP address set
to 0.0.0.0 to bring the number of entries up to
.Dq mirror_level .
It can be used by a system administrator to prepare a file for mirroring
via the
.Xr pnfsdscopymr
command with
.Fl r
option.
.It Fl r Ar dshostname
This option sets the IP address of the extended attribute entry for the
.Ar dshostname
to 0.0.0.0 so that it will no longer be used.
.Pp
This is meant to be used when mirroring is enabled and the
.Ar dshostname
DS is disabled, so that it can be re-enabled once it is repaired.
This needs to be done for all files in the exported MDS tree where
the data may not be up-to-date on the repaired DS when it is re-enabled.
After being re-enabled, the command
.Xr pnfsdscopymr 1
with the
.Dq -r
option
will be used to copy the the file's data to this repaired DS and then update the
extended attribute to use it.
.Pp
A typical use of this will be within a
.Xr find 1
for all regular files in the MDS's exported tree.
.sp
For example, if the disabled DS is nfsv4-data3:
.br
# cd <top-level-exported-directory-on-MDS>
.br
# find . -type f -exec pnfsdsfile -q -r nfsv4-data3 {} \\;
.El
.Sh SEE ALSO
.Xr find 1 ,
.Xr getaddrinfo 3 ,
.Xr nfsv4 4 ,
.Xr pnfs 4 ,
.Xr nfsd 8 ,
.Xr pnfsdscopymr 8 ,
.Xr pnfsdskill 8
.Sh HISTORY
The
.Nm
command first appeared in
.Fx 12.0 .