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>