.TH MULTIPATH 8 "July 2006" "" "Linux Administrator's Manual"
.SH NAME
multipath \- Device mapper target autoconfig
.SH SYNOPSIS
.B multipath
.RB [\| \-v\ \c
.IR verbosity \|]
.RB [\| \-d \|]
.RB [\| \-h | \-l | \-ll | \-f | \-F \|]
.RB [\| \-p\ \c
.BR failover | multibus | group_by_serial | group_by_prio | group_by_node_name \|]
.RB [\| device \|]
.SH DESCRIPTION
.B multipath
is used to detect multiple paths to devices for fail-over or performance reasons and coalesces them
.SH OPTIONS
.TP
.B \-v " level"
verbosity, print all paths and multipaths
.RS 1.2i
.TP 1.2i
.B 0
no output
.TP
.B 1
print the created or updated multipath names only, for use to feed other tools like kpartx
.TP
.B 2 +
print all info : detected paths, coalesced paths (ie multipaths) and device maps
.RE
.TP
.B \-h
print usage text
.TP
.B \-d
dry run, do not create or update devmaps
.TP
.B \-l
show the current multipath topology from information fetched in sysfs and the device mapper
.TP
.B \-ll
show the current multipath topology from all available information (sysfs, the device mapper, path checkers ...)
.TP
.B \-f
flush a multipath device map specified as parameter, if unused
.TP
.B \-F
flush all unused multipath device maps
.TP
.BI \-p " policy"
force maps to specified policy:
.RS 1.2i
.TP 1.2i
.B failover
1 path per priority group
.TP
.B multibus
all paths in 1 priority group
.TP
.B group_by_serial
1 priority group per serial
.TP
.B group_by_prio
1 priority group per priority value. Priorities are determined by callout programs specified as a global, per-controller or per-multipath option in the configuration file
.TP
.B group_by_node_name
1 priority group per target node name. Target node names are fetched in /sys/class/fc_transport/target*/node_name.
.RE
.TP
.BI device
update only the devmap the path pointed by
.I device
is in. 
.I device
is in the /dev/sdb (as shown by udev in the $DEVNAME variable) or major:minor format.
.I device
may alternatively be a multipath mapname
.SH "SEE ALSO"
.BR udev (8),
.BR dmsetup (8)
.BR hotplug (8)
.SH AUTHORS
.B multipath
was developed by Christophe Varoqui, <christophe.varoqui@opensvc.com> and others.