multipathd(8)
NAME
multipathd - multipath daemon
SYNOPSIS
multipathd [options]
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 config 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.
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,
e.g. 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 any 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
multipathd was developed by Christophe Varoqui, <[email protected]> and others.
Opportunity
Personal Opportunity - Free software gives you access to billions of dollars of software at no cost. Use this software for your business, personal use or to develop a profitable skill. Access to source code provides access to a level of capabilities/information that companies protect though copyrights. Open source is a core component of the Internet and it is available to you. Leverage the billions of dollars in resources and capabilities to build a career, establish a business or change the world. The potential is endless for those who understand the opportunity.
Business Opportunity - Goldman Sachs, IBM and countless large corporations are leveraging open source to reduce costs, develop products and increase their bottom lines. Learn what these companies know about open source and how open source can give you the advantage.
Free Software
Free Software provides computer programs and capabilities at no cost but more importantly, it provides the freedom to run, edit, contribute to, and share the software. The importance of free software is a matter of access, not price. Software at no cost is a benefit but ownership rights to the software and source code is far more significant.
Free Office Software - The Libre Office suite provides top desktop productivity tools for free. This includes, a word processor, spreadsheet, presentation engine, drawing and flowcharting, database and math applications. Libre Office is available for Linux or Windows.
Free Books
The Free Books Library is a collection of thousands of the most popular public domain books in an online readable format. The collection includes great classical literature and more recent works where the U.S. copyright has expired. These books are yours to read and use without restrictions.
Source Code - Want to change a program or know how it works? Open Source provides the source code for its programs so that anyone can use, modify or learn how to write those programs themselves. Visit the GNU source code repositories to download the source.
Education
Study at Harvard, Stanford or MIT - Open edX provides free online courses from Harvard, MIT, Columbia, UC Berkeley and other top Universities. Hundreds of courses for almost all major subjects and course levels. Open edx also offers some paid courses and selected certifications.
Linux Manual Pages - A man or manual page is a form of software documentation found on Linux/Unix operating systems. Topics covered include computer programs (including library and system calls), formal standards and conventions, and even abstract concepts.
