NAME

       blkmapd - pNFS block layout mapping daemon

SYNOPSIS

       blkmapd [-h] [-d] [-f]

DESCRIPTION

       The blkmapd daemon performs device discovery and mapping for the parallel NFS (pNFS) block
       layout client [RFC5663].

       The pNFS block layout protocol builds a complex storage hierarchy from  a  set  of  simple
       volumes.   These  simple volumes are addressed by content, using a signature on the volume
       to uniquely name each one.  The daemon locates a volume by examining each block device  in
       the system for the given signature.

       The  topology typically consists of a hierarchy of volumes built by striping, slicing, and
       concatenating the simple volumes.  The blkmapd daemon uses  the  device-mapper  driver  to
       construct  logical  devices  that reflect the server topology, and passes these devices to
       the kernel for use by the pNFS block layout client.

OPTIONS

       -h     Display usage message.

       -d     Performs device discovery only then exits.

       -f     Runs blkmapd in the foreground and sends output to stderr (as opposed to syslogd)

CONFIGURATION FILE

       The blkmapd daemon recognizes the following  value  from  the  [general]  section  of  the
       /etc/nfs.conf configuration file:

       pipefs-directory
              Tells  blkmapd  where  to look for the rpc_pipefs filesystem.  The default value is
              /var/lib/nfs/rpc_pipefs.

SEE ALSO

       nfs(5), dmsetup(8), nfs.conf(5)

       RFC 5661 for the NFS version 4.1 specification.
       RFC 5663 for the pNFS block layout specification.

AUTHORS

       Haiying Tang <Tang_Haiying@emc.com>
       Jim Rees <rees@umich.edu>

                                          11 August 2011                               blkmapd(8)