multipath man 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|-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@opensvc.com> and others.

Referenced By

kpartx(8), mpathconf(8), multipath.conf(5), multipathd(8).

July 2006 Linux Administrator's Manual