x SuSE Linux 13.1-RELEASE x
x SuSE Linux 13.1-RELEASEx
MULTIPATH(8) System Manager's Manual MULTIPATH(8)
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 se-
lects 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 de-
vices.
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 de-
vices.
-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 /etc/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 mod-
ified multipath maps are printed. In list mode,
WWIDs of all multipath maps are printed.
2 In default mode, Topology of created or modi-
fied multipath maps is printed. In list mode,
topology of all multipath maps is printed.
3 All detected paths and the topology of all mul-
tipath maps are printed.
The verbosity level also controls the level of log and de-
bug messages printed to stderr. The default level corre-
sponds 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 /etc/multipath.conf, mul-
tipath 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 /etc/multipath.conf(5). This option
should only be used in rare circumstances.
-B Treat the bindings file as read only.
-b file
(deprecated, do not use) 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 mul-
tipath 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 con-
figuration in multipath.conf(5). The possible values for policy
are the same as the values for path_grouping_policy in multi-
path.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), hot-
plug(8).
AUTHORS
multipath-tools was developed by Christophe Varoqui <christophe.varo-
qui@opensvc.com> and others.
Linux 2021-11-12 MULTIPATH(8)
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