blkmapd — pNFS block layout mapping daemon
Synopsis
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.
Referenced By
blkmapd_selinux(8), nfs.conf(5).