1MULTIPATH(8) System Manager's Manual MULTIPATH(8)
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6 multipath - Device mapper target autoconfig.
7
9 multipath [-v level] [-B|-d|-i|-q|-r] [-b file] [-p policy] [device]
10 multipath [-v level] [-R retries] -f device
12 multipath [-v level] [-R retries] -F
14 multipath [-v level] [-l|-ll] [device]
16 multipath [-v level] [-a|-w] device
18 multipath [-v level] [-A|-W]
20 multipath [-v level] [-i] [-c|-C] device
22 multipath [-v level] [-i] [-u|-U]
24 multipath [-h|-t|-T]
26
28 multipath is used to detect and coalesce multiple paths to devices, for
29 fail-over or performance reasons.
30
32 The device argument restricts multipath's operation to devices matching
33 the given expression. The argument may refer either to a multipath map
34 or to its components ("paths"). The expression may be in one of the
35 following formats:
36 device node file name of a device node, e.g. /dev/dm-10 or /dev/sda.
38 If the node refers to an existing device mapper device
39 representing a multipath map, this selects the map or its
40 paths, depending on the operation mode. Otherwise, it se‐
41 lects a path device.
42 device ID kernel device number specified by major:minor numbers,
44 e.g. 65:16. This format can only be used for path de‐
45 vices.
46 WWID a World Wide Identifier matching a multipath map or its
48 paths. To list WWIDs of devices present in the system,
49 use e.g. the command "multipath -d -v3 2>/dev/null".
50
52 The default operation mode is to detect and set up multipath maps from
53 the devices found in the system. Other operation modes are chosen by
54 using one of the following command line switches:
55 -f Flush (remove) a multipath device map specified as parameter, if
57 unused. This operation is delegated to the multipathd daemon if
58 it's running.
59 -F Flush (remove) all unused multipath device maps. This operation
61 is delegated to the multipathd daemon if it's running.
62 -l Show ("list") the current multipath topology from information
64 fetched in sysfs and the device mapper.
65 -ll Show ("list") the current multipath topology from all available
67 information (sysfs, the device mapper, path checkers ...).
68 -a Add the WWID for the specified device to the WWIDs file.
70 -A Add the WWIDs from any kernel command line mpath.wwid parameters
72 to the WWIDs file.
73 -w Remove the WWID for the specified device from the WWIDs file.
75 -W Reset the WWIDs file to only include the current multipath de‐
77 vices.
78 -c Check if a block device should be a path in a multipath device.
80 -C Check if a multipath device has usable paths. This can be used
82 to test whether or not I/O on this device is likely to succeed.
83 The command itself doesn't attempt to do I/O on the device.
84 -u Check if the device specified in the program environment should
86 be a path in a multipath device.
87 -U Check if the device specified in the program environment is a
89 multipath device with usable paths. See -C.
90 -h Print usage text.
92 -t Display the currently used multipathd configuration.
94 -T Display the currently used multipathd configuration, limiting
96 the output to those devices actually present in the system. This
97 can be used a template for creating multipath.conf.
98
100 -v level
101 Verbosity of information printed to stdout in default and "list"
102 operation modes. The default level is -v 2.
103 0 Nothing is printed.
105 1 In default mode, Names/WWIDs of created or mod‐
107 ified multipath maps are printed. In list mode,
108 WWIDs of all multipath maps are printed.
109 2 In default mode, Topology of created or modi‐
111 fied multipath maps is printed. In list mode,
112 topology of all multipath maps is printed.
113 3 All detected paths and the topology of all mul‐
115 tipath maps are printed.
116 The verbosity level also controls the level of log and de‐
118 bug messages printed to stderr. The default level corre‐
119 sponds to LOG_NOTICE (important messages that shouldn't be
120 missed in normal operation).
121 -d Dry run, do not create or update devmaps.
123 -e Enable all foreign libraries. This overrides the enable_foreign
125 option from multipath.conf(5).
126 -i Ignore WWIDs file when processing devices. If find_multipaths
128 strict or find_multipaths no is set in multipath.conf, multipath
129 only considers devices that are listed in the WWIDs file. This
130 option overrides that behavior. For other values of find_multi‐
131 paths, this option has no effect. See the description of
132 find_multipaths in multipath.conf(5). This option should only
133 be used in rare circumstances.
134 -B Treat the bindings file as read only.
136 -b file
138 Set user_friendly_names bindings file location. The default is
139 /etc/multipath/bindings.
140 -q Don't unset the device mapper feature queue_if_no_path for mul‐
142 tipath maps. Normally, multipath would do so if multipathd is
143 not running, because only a running multipath daemon guarantees
144 that unusable paths are reinstated when they become usable
145 again.
146 -p policy
148 Force new maps to use the specified policy, overriding the con‐
149 figuration in multipath.conf(5). The possible values for policy
150 are the same as the values for path_grouping_policy in multi‐
151 path.conf(5). Existing maps are not modified.
152 -r Force a reload of all existing multipath maps. This command is
154 delegated to the multipathd daemon if it's running. In this
155 case, other command line switches of the multipath command have
156 no effect.
157 -R retries
159 Number of times to retry flushing multipath devices that are in
160 use. The default is 0.
161
163 multipathd(8), multipath.conf(5), kpartx(8), udev(8), dmsetup(8), hot‐
164 plug(8).
165
167 multipath-tools was developed by Christophe Varoqui <christophe.varo‐
168 qui@opensvc.com> and others.
169Linux 2018-10-10 MULTIPATH(8)