NAME

       multipathd - Multipath daemon.

SYNOPSIS

       multipathd [-d|-k] [-s] [-v verbosity] [-B] [-w]

DESCRIPTION

       The  multipathd  daemon is in charge of checking for failed paths. When this happens, it will reconfigure
       the multipath map the path belongs to, so that this map regains its maximum performance and redundancy.

       This daemon executes the external multipath tool when events occur.  In turn, the multipath tool  signals
       the multipathd daemon when it is done with devmap reconfiguration, so that it can refresh its failed path
       list.

OPTIONS

       -d     Foreground Mode. Don't daemonize, and print all messages to stdout and stderr.

       -s     Suppress timestamps. Do not prefix logging messages with a timestamp.

       -v level
              Verbosity level. Print additional information while running multipathd. A  level of 0  means  only
              print errors. A level of 3 or greater prints debugging information as well.

       -B     Read-only  bindings file. multipathd will not write to the user_friendly_names bindings file. If a
              user_friendly_name doesn't already exist for a device, it will use its WWID as its alias.

       -k     multipathd will enter interactive mode. From this mode, the available commands can  be  viewed  by
              entering 'help'. When you are finished entering commands, press CTRL-D to quit.

       -n     IGNORED.  Use  the  option  find_multipaths  to control the treatment of newly detected devices by
              multipathd. See multipath.conf(5).

       -w     Since kernel 4.14 a new device-mapper event polling  interface  is  used  for  updating  multipath
              devices  on  dmevents.  Use  this  flag  to force it to use the old event waiting method, based on
              creating a seperate thread for each device.

COMMANDS

       The following commands can be used in interactive mode:

       list|show paths
              Show the paths that multipathd is monitoring, and their state.

       list|show paths format $format
              Show the paths that multipathd is monitoring, using a format string with path format wildcards.

       list|show maps|multipaths
              Show the multipath devices that the multipathd is monitoring.

       list|show maps|multipaths format $format
              Show the status of all multipath devices that the multipathd is monitoring, using a format  string
              with multipath format wildcards.

       list|show maps|multipaths status
              Show the status of all multipath devices that the multipathd is monitoring.

       list|show maps|multipaths stats
              Show some statistics of all multipath devices that the multipathd is monitoring.

       list|show maps|multipaths topology
              Show the current multipath topology. Same as 'multipath -ll'.

       list|show topology
              Show the current multipath topology. Same as 'multipath -ll'.

       list|show map|multipath $map topology
              Show    topology    of    a   single   multipath   device   specified   by   $map,   for   example
              36005076303ffc56200000000000010aa. This map could be obtained from 'list maps'.

       list|show wildcards
              Show the format wildcards used in interactive commands taking $format.

       list|show config
              Show the currently used configuration, derived from default values and values specified within the
              configuration file /etc/multipath.conf.

       list|show config local
              Show  the currently used configuration like show config, but limiting the devices section to those
              devices that are actually present in the system.

       list|show blacklist
              Show the currently used blacklist rules, derived from default values and values  specified  within
              the configuration file /etc/multipath.conf.

       list|show devices
              Show all available block devices by name including the information if they are blacklisted or not.

       list|show status
              Show  the  number  of  path  checkers  in  each possible state, the number of monitored paths, and
              whether multipathd is currently handling a uevent.

       list|show daemon
              Show the current state of the multipathd daemon.

       add path $path
              Add a path to the list of monitored paths. $path is as listed in /sys/block (e.g. sda).

       remove|del path $path
              Stop monitoring a path. $path is as listed in /sys/block (e.g. sda).

       add map|multipath $map
              Add a multipath device to the list of monitored devices. $map can either be a device-mapper device
              as  listed in /sys/block (e.g. dm-0) or it can be the alias for the multipath device (e.g. mpath1)
              or the uid of the multipath device (e.g. 36005076303ffc56200000000000010aa).

       remove|del map|multipath $map
              Stop monitoring a multipath device.

       resize map|multipath $map
              Resizes map $map to the given size.

       switch|switchgroup map|multipath $map group $group
              Force a multipath device to switch to a specific path group.  $group  is  the  path  group  index,
              starting with 1.

       reconfigure
              Reconfigures the multipaths. This should be triggered automatically after anyi hotplug event.

       suspend map|multipath $map
              Sets map $map into suspend state.

       resume map|multipath $map
              Resumes map $map from suspend state.

       reset map|multipath $map
              Reassign  existing  device-mapper  table(s)  use  use  the  multipath  device, instead of its path
              devices.

       reload map|multipath $map
              Reload a multipath device.

       fail path $path
              Sets path $path into failed state.

       reinstate path $path
              Resumes path $path from failed state.

       disablequeueing maps|multipaths
              Disable queueing on all multipath devices.

       restorequeueing maps|multipaths
              Restore queueing on all multipath devices.

       disablequeueing map|multipath $map
              Disable queuing on multipathed map $map.

       restorequeueing map|multipath $map
              Restore queuing on multipahted map $map.

       forcequeueing daemon
              Forces multipathd into queue_without_daemon mode, so  that  no_path_retry  queueing  will  not  be
              disabled when the daemon stops.

       restorequeueing daemon
              Restores configured queue_without_daemon mode.

       map|multipath $map setprstatus
              Enable persistent reservation management on $map.

       map|multipath $map unsetprstatus
              Disable persistent reservation management on $map.

       map|multipath $map getprstatus
              Get the current persistent reservation management status of $map.

       map|multipath $map getprkey
              Get the current persistent reservation key associated with $map.

       map|multipath $map setprkey key $key
              Set  the persistent reservation key associated with $map to $key in the prkeys_file. This key will
              only be used by multipathd if reservation_key is set to file in /etc/multipath.conf.

       map|multipath $map unsetprkey
              Remove the persistent reservation key associated with $map from the prkeys_file.  This  will  only
              unset the key used by multipathd if reservation_key is set to file in /etc/multipath.conf.

       path $path setmarginal
              move  $path  to  a  marginal  pathgroup.  The  path  will  remain in the marginal path group until
              unsetmarginal is called. This command will only work if marginal_pathgroups is enabled  and  there
              is no Shaky paths detection method configured (see the multipath.conf man page for details).

       path $path unsetmarginal
              return   marginal   path   $path  to  its  normal  pathgroup.  This  command  will  only  work  if
              marginal_pathgroups is enabled and there is no Shaky paths detection method  configured  (see  the
              multipath.conf man page for details).

       map $map unsetmarginal
              return  all  marginal  paths  in  $map  to their normal pathgroups. This command will only work if
              marginal_pathgroups is enabled and there is no Shaky paths detection method  configured  (see  the
              multipath.conf man page for details).

       quit|exit
              End interactive session.

       shutdown
              Stop multipathd.

SYSTEMD INTEGRATION

       When  compiled  with  systemd  support  two  systemd  service files are installed, multipathd.service and
       multipathd.socket The multipathd.socket service instructs systemd to intercept the CLI command socket, so
       that  any  call  to  the CLI interface will start-up the daemon if required.  The multipathd.service file
       carries the definitions for controlling the multipath daemon. The daemon  itself  uses  the  sd_notify(3)
       interface to communicate with systemd. The following unit keywords are recognized:

       WatchdogSec=
              Enables the internal watchdog from systemd. multipath will send a notification via sd_notify(3) to
              systemd to reset the watchdog. If specified the polling_interval and max_polling_interval settings
              will  be  overridden  by the watchdog settings.  Please note that systemd prior to version 207 has
              issues which prevent the systemd-provided watchdog from working correctly. So the watchdog is  not
              enabled per default, but has to be enabled manually by updating the multipathd.service file.

       OOMScoreAdjust=
              Overrides the internal OOM adjust mechanism.

       LimitNOFILE=
              Overrides the max_fds configuration setting.

SEE ALSO

       multipath(8), kpartx(8), sd_notify(3), system.service(5).

AUTHORS

       multipath-tools was developed by Christophe Varoqui <christophe.varoqui@opensvc.com> and others.