multipath (8) Linux Manual Page

multipath – Device mapper target autoconfig

Synopsis

multipath [-v verbosity] [-b bindings_file] [-d] [-h|-l|-ll|-f|-t|-F|-B|-c|-q|-r|-r|-a|-A|-w|] [-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

-i

ignore wwids file when processing devices

-B

treat the bindings file as read only

-b bindings_file

set user_friendly_names bindings file location. The default is /etc/multipath/bindings

-c

check if a block device should be a path in a multipath device

-q

allow device tables with queue_if_no_path when multipathd is not running

-a

add the wwid for the specified device to the wwids file

-A

add wwids from any kernel command line mpath.wwid parameters to the wwids file

-w

remove the wwid for the specified device from the wwids file

-W

reset the wwids file to only include the current multipath devices

-T tm:valid

check if tm matches the multipathd configuration timestamp value from /run/multipathd/timestamp If so, return success if valid is 1. Otherwise, return failure. If the timestamp doesn’t match continue with multipath execution. This option is designed to be used with -c by the udev rules.

-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-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_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 [at] opensvc.com> and others.