1MULTIPATH(8)                System Manager's Manual               MULTIPATH(8)
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NAME

6       multipath - Device mapper target autoconfig.
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SYNOPSIS

9       multipath [-v level] [-B|-d|-i|-q|-r] [-b file] [-p policy] [device]
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11       multipath [-v level] [-R retries] -f device
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13       multipath [-v level] [-R retries] -F
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15       multipath [-v level] [-l|-ll] [device]
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17       multipath [-v level] [-a|-w] device
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19       multipath [-v level] [-A|-W]
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21       multipath [-v level] [-i] [-c|-C] device
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23       multipath [-v level] [-i] [-u|-U]
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25       multipath [-h|-t|-T]
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DESCRIPTION

28       multipath is used to detect and coalesce multiple paths to devices, for
29       fail-over or performance reasons.
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ARGUMENTS

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
37       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
41                     selects a path device.
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43       device ID     kernel  device  number  specified by major:minor numbers,
44                     e.g. 65:16.  This  format  can  only  be  used  for  path
45                     devices.
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47       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".
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OPERATION MODES

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:
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56       -f     Flush (remove) a multipath device map specified as parameter, if
57              unused.
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59       -F     Flush (remove) all unused multipath device maps.
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61       -l     Show ("list") the current multipath  topology  from  information
62              fetched in sysfs and the device mapper.
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64       -ll    Show  ("list") the current multipath topology from all available
65              information (sysfs, the device mapper, path checkers ...).
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67       -a     Add the WWID for the specified device to the WWIDs file.
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69       -A     Add the WWIDs from any kernel command line mpath.wwid parameters
70              to the WWIDs file.
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72       -w     Remove the WWID for the specified device from the WWIDs file.
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74       -W     Reset  the  WWIDs  file  to  only  include the current multipath
75              devices.
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77       -c     Check if a block device should be a path in a multipath device.
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79       -C     Check if a multipath device has usable paths. This can  be  used
80              to  test whether or not I/O on this device is likely to succeed.
81              The command itself doesn't attempt to do I/O on the device.
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83       -u     Check if the device specified in the program environment  should
84              be a path in a multipath device.
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86       -U     Check  if  the  device specified in the program environment is a
87              multipath device with usable paths. See -C.
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89       -h     Print usage text.
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91       -t     Display the currently used multipathd configuration.
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93       -T     Display the currently used  multipathd  configuration,  limiting
94              the output to those devices actually present in the system. This
95              can be used a template for creating multipath.conf.
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OPTIONS

98       -v level
99              Verbosity of information printed to stdout in default and "list"
100              operation modes. The default level is -v 2.
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102                   0           Nothing is printed.
103
104                   1           In default mode, Names/WWIDs of created or mod‐
105                               ified multipath maps are printed. In list mode,
106                               WWIDs of all multipath maps are printed.
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108                   2           In  default  mode, Topology of created or modi‐
109                               fied multipath maps is printed.  In list  mode,
110                               topology of all multipath maps is printed.
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112                   3           All detected paths and the topology of all mul‐
113                               tipath maps are printed.
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115                   The verbosity level also controls  the  level  of  log  and
116                   debug  messages printed to stderr. The default level corre‐
117                   sponds to LOG_NOTICE (important messages that shouldn't  be
118                   missed in normal operation).
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120       -d     Dry run, do not create or update devmaps.
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122       -i     Ignore  WWIDs  file  when processing devices. If find_multipaths
123              strict or find_multipaths no is set in multipath.conf, multipath
124              only  considers  devices that are listed in the WWIDs file. This
125              option overrides that behavior. For other values of  find_multi‐
126              paths,  this  option  has  no  effect.  See  the  description of
127              find_multipaths in multipath.conf(5).  This option  should  only
128              be used in rare circumstances.
129
130       -B     Treat the bindings file as read only.
131
132       -b file
133              Set  user_friendly_names bindings file location.  The default is
134              /etc/multipath/bindings.
135
136       -q     Don't unset the device mapper feature queue_if_no_path for  mul‐
137              tipath  maps.  Normally,  multipath would do so if multipathd is
138              not running, because only a running multipath daemon  guarantees
139              that  unusable  paths  are  reinstated  when  they become usable
140              again.
141
142       -p policy
143              Force new maps to use the specified policy, overriding the  con‐
144              figuration  in multipath.conf(5). The possible values for policy
145              are the same as the values for  path_grouping_policy  in  multi‐
146              path.conf(5). Existing maps are not modified.
147
148       -r     Force  a  reload of all existing multipath maps. This command is
149              delegated to the multipathd daemon  if  it's  running.  In  this
150              case,  other command line switches of the multipath command have
151              no effect.
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153       -R retries
154              Number of times to retry flushing multipath devices that are  in
155              use. The default is 0.
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SEE ALSO

158       multipathd(8),  multipath.conf(5), kpartx(8), udev(8), dmsetup(8), hot‐
159       plug(8).
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AUTHORS

162       multipath-tools was developed by Christophe  Varoqui  <christophe.varo‐
163       qui@opensvc.com> and others.
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167Linux                             2018-10-10                      MULTIPATH(8)
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