MULTIPATH(8) Linux Administrator's Manual MULTIPATH(8)NAMEmultipath - Device mapper target autoconfig
SYNOPSISmultipath [-v verbosity] [-d] [-h|-l|-ll|-f|-F|-B|-r|-q] [-b filename]
[-p failover|multibus|group_by_serial|group_by_prio|group_by_node_name]
[device]
DESCRIPTIONmultipath 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
-b file
set the location of the user_friendly_names bindings file.
-q allow devices to set queue_if_no_path while multipathd is not
running.
-l show the current multipath topology from information fetched in
sysfs and the device mapper
-ll show the current multipath topology from all available informa‐
tion (sysfs, the device mapper, path checkers ...)
-f flush a multipath device map specified as parameter, if unused
-F flush all unused multipath device maps
-r force maps to reload
-B treat the bindings file as read only
-p policy
force maps to 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-controller 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_trans‐
port/target*/node_name.
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
NOTES
a map may be unused if, eg, the file system on it is not mounted or
there are no open file descriptors against the device file, as in a raw
device.
SEE ALSOudev(8), dmsetup(8)hotplug(8)AUTHORSmultipath was developed by Christophe Varoqui, <christophe.varo‐
qui@free.fr> and others.
July 2006 MULTIPATH(8)
