Provided by: multipath-tools_0.9.4-5ubuntu8_amd64 
NAME
multipath - Device mapper target autoconfig.
SYNOPSIS
multipath [-v level] [-B|-d|-i|-q|-r] [-b file] [-p policy] [device]
multipath [-v level] [-R retries] -f device
multipath [-v level] [-R retries] -F
multipath [-v level] [-l|-ll] [device]
multipath [-v level] [-a|-w] device
multipath [-v level] -W
multipath [-v level] [-i] [-c|-C] device
multipath [-v level] [-i] [-u|-U]
multipath [-h|-t|-T]
DESCRIPTION
multipath is used to detect and coalesce multiple paths to devices, for fail-over or performance reasons.
ARGUMENTS
The device argument restricts multipath's operation to devices matching the given expression. The
argument may refer either to a multipath map or to its components ("paths"). The expression may be in one
of the following formats:
device node file name of a device node, e.g. /dev/dm-10 or /dev/sda. If the node refers to an existing
device mapper device representing a multipath map, this selects the map or its paths,
depending on the operation mode. Otherwise, it selects a path device.
device ID kernel device number specified by major:minor numbers, e.g. 65:16. This format can only be
used for path devices.
WWID a World Wide Identifier matching a multipath map or its paths. To list WWIDs of devices
present in the system, use e.g. the command "multipath -d -v3 2>/dev/null".
OPERATION MODES
The default operation mode is to detect and set up multipath maps from the devices found in the system.
Other operation modes are chosen by using one of the following command line switches:
-f Flush (remove) a multipath device map specified as parameter, if unused. This operation is
delegated to the multipathd daemon if it's running.
-F Flush (remove) all unused multipath device maps. This operation is delegated to the multipathd
daemon if it's running.
-l Show ("list") the current multipath topology from information fetched in sysfs and the device
mapper.
-ll Show ("list") the current multipath topology from all available information (sysfs, the device
mapper, path checkers ...).
-a Add the WWID for the specified device 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.
-c Check if a block device should be a path in a multipath device.
-C Check if a multipath device has usable paths. This can be used to test whether or not I/O on this
device is likely to succeed. The command itself doesn't attempt to do I/O on the device.
-u Check if the device specified in the program environment should be a path in a multipath device.
-U Check if the device specified in the program environment is a multipath device with usable paths.
See -C.
-h Print usage text.
-t Display the currently used multipathd configuration.
-T Display the currently used multipathd configuration, limiting the output to those devices actually
present in the system. This can be used a template for creating multipath.conf.
OPTIONS
-v level
Verbosity of information printed to stdout in default and "list" operation modes. The default
level is -v 2.
0 Nothing is printed.
1 In default mode, Names/WWIDs of created or modified multipath maps are printed.
In list mode, WWIDs of all multipath maps are printed.
2 In default mode, Topology of created or modified multipath maps is printed. In
list mode, topology of all multipath maps is printed.
3 All detected paths and the topology of all multipath maps are printed.
The verbosity level also controls the level of log and debug messages printed to stderr. The
default level corresponds to LOG_NOTICE (important messages that shouldn't be missed in
normal operation).
-d Dry run, do not create or update devmaps.
-e Enable all foreign libraries. This overrides the enable_foreign option from multipath.conf(5).
-i Ignore WWIDs file when processing devices. If find_multipaths strict or find_multipaths no is set
in multipath.conf, multipath only considers devices that are listed in the WWIDs file. This option
overrides that behavior. For other values of find_multipaths, this option has no effect. See the
description of find_multipaths in multipath.conf(5). This option should only be used in rare
circumstances.
-B Treat the bindings file as read only.
-b file
Set user_friendly_names bindings file location. The default is /etc/multipath/bindings.
-q Don't unset the device mapper feature queue_if_no_path for multipath maps. Normally, multipath
would do so if multipathd is not running, because only a running multipath daemon guarantees that
unusable paths are reinstated when they become usable again.
-p policy
Force new maps to use the specified policy, overriding the configuration in multipath.conf(5). The
possible values for policy are the same as the values for path_grouping_policy in
multipath.conf(5). Existing maps are not modified.
-r Force a reload of all existing multipath maps. This command is delegated to the multipathd daemon
if it's running. In this case, other command line switches of the multipath command have no
effect.
-R retries
Number of times to retry flushing multipath devices that are in use. The default is 0.
SEE ALSO
multipathd(8), multipath.conf(5), kpartx(8), udev(8), dmsetup(8), hotplug(8).
AUTHORS
multipath-tools was developed by Christophe Varoqui <christophe.varoqui@opensvc.com> and others.
Linux 2021-11-12 MULTIPATH(8)