multipathd man page

multipathd — Multipath daemon.

Synopsis

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

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.

In this Linux distribution, multipathd does not run unless a /etc/multipath.conffile exists

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

Ignore new devices. multipathd will not create a multipath device unless the WWID for the device is already listed in the WWIDs file.

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 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.

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.

Referenced By

blkdeactivate(8), kpartx(8), mpathconf(8), mpathpersist(8), multipath(8), multipath.conf(5).

2016-10-27 Linux