Section: Maintenance Commands (8)
multipath - Device mapper target autoconfig.
is used to detect and coalesce multiple paths to devices, for fail-over or performance reasons.
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.
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".
The default operation mode is to detect and set up multipath maps from the devices found in
Other operation modes are chosen by using one of the following command line switches:
Flush (remove) a multipath device map specified as parameter, if unused.
Flush (remove) all unused multipath device maps.
Show ("list") the current multipath topology from information fetched in sysfs and the device mapper.
Show ("list") the current multipath topology from all available information (sysfs, the
device mapper, path checkers ...).
Add the WWID for the specified device to the WWIDs file.
Add the WWIDs from any kernel command line mpath.wwid parameters to the
Remove the WWID for the specified device from the WWIDs file.
Reset the WWIDs file to only include the current multipath devices.
Check if a block device should be a path in a multipath device.
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.
Check if the device specified in the program environment should be
a path in a multipath device.
Check if the device specified in the program environment is a multipath device
with usable paths. See -C.
Print usage text.
Display the currently used multipathd configuration.
Display the currently used multipathd configuration, limiting the output to
those devices actually present in the system. This can be used a template for
- -v level
Verbosity of information printed to stdout in default and "list" operation
modes. The default level is -v 2.
Nothing is printed.
In default mode, Names/WWIDs of created or modified multipath maps are
printed. In list mode, WWIDs of all multipath maps are printed.
In default mode,
Topology of created or modified multipath maps is printed.
In list mode, topology of all multipath maps is printed.
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).
Dry run, do not create or update devmaps.
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
This option should only be used in rare circumstances.
Treat the bindings file as read only.
- -b file
Set user_friendly_names bindings file location. The default is
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.
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
was developed by Christophe Varoqui <email@example.com