MULTIPATH(8)						   Linux Administrator's Manual 					      MULTIPATH(8)

NAME

       multipath - Device mapper target autoconfig

SYNOPSIS

       multipath [-v verbosity] [-d] [-h|-l|-ll|-f|-t|-F-B] [-p failover|multibus|group_by_serial|group_by_prio|group_by_node_name] [device]

DESCRIPTION

       multipath is used to detect multiple paths to devices for fail-over or performance reasons and coalesces them

OPTIONS

       -v  level
	      verbosity, print all paths and multipaths

		   0	       no output

		   1	       print the created or updated multipath names only, for use to feed other tools like kpartx

		   2 +	       print all info : detected paths, coalesced paths (ie multipaths) and device maps

       -h     print usage text

       -d     dry run, do not create or update devmaps

       -l     show the current multipath topology from information fetched in sysfs and the device mapper

       -ll    show the current multipath topology from all available information (sysfs, the device mapper, path checkers ...)

       -f     flush a multipath device map specified as parameter, if unused

       -F     flush all unused multipath device maps

       -t     print internal hardware table to stdout

       -r     force devmap reload

       -B     treat the bindings file as read only

       -p policy
	      force new maps to use the specified policy:

		   failover    1 path per priority group

		   multibus    all paths in 1 priority group

		   group_by_serial
			       1 priority group per serial

		   group_by_prio
			       1  priority group per priority value. Priorities are determined by callout programs specified as a global, per-con-
			       troller or per-multipath option in the configuration file

		   group_by_node_name
			       1 priority group per target node name. Target node names are fetched in /sys/class/fc_transport/target*/node_name.

	      Existing maps are not modified.

       device update only the devmap the path pointed by device is in.	device is in the /dev/sdb (as shown by udev in the $DEVNAME  variable)	or
	      major:minor format.  device may alternatively be a multipath mapname

SEE ALSO

       multipathd(8), multipath.conf(5), kpartx(8), udev(8), dmsetup(8) hotplug(8)

AUTHORS

       multipath was developed by Christophe Varoqui, <christophe.varoqui@opensvc.com> and others.

								     July 2006							      MULTIPATH(8)