.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 | \-t | \-F \| \-B \|]
.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
.B \-t
print internal hardware table to stdout
.TP
.B \-r
force devmap reload
.TP
.B \-B
treat the bindings file as read only
.TP
.BI \-p " policy"
force new maps to use the 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.
.TP
.RE
Existing maps are not modified.
.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 multipathd (8),
.BR multipath.conf (5),
.BR kpartx (8),
.BR udev (8),
.BR dmsetup (8)
.BR hotplug (8)
.SH AUTHORS
.B multipath
was developed by Christophe Varoqui, <christophe.varoqui@opensvc.com> and others.