multipath(8) [linux man page]
MULTIPATH(8) Linux Administrator's Manual MULTIPATH(8) NAME
multipath - Device mapper target autoconfig SYNOPSIS
multipath [-v verbosity] [-d] [-h|-l|-ll|-f|-t|-F-B] [-p failover|multibus|group_by_serial|group_by_prio|group_by_node_name] [device] DESCRIPTION
multipath is used to detect multiple paths to devices for fail-over or performance reasons and coalesces them OPTIONS
-v level verbosity, print all paths and multipaths 0 no output 1 print the created or updated multipath names only, for use to feed other tools like kpartx 2 + print all info : detected paths, coalesced paths (ie multipaths) and device maps -h print usage text -d dry run, do not create or update devmaps -l show the current multipath topology from information fetched in sysfs and the device mapper -ll show the current multipath topology from all available information (sysfs, the device mapper, path checkers ...) -f flush a multipath device map specified as parameter, if unused -F flush all unused multipath device maps -t print internal hardware table to stdout -r force devmap reload -B treat the bindings file as read only -p policy force new maps to use the specified policy: failover 1 path per priority group multibus all paths in 1 priority group group_by_serial 1 priority group per serial group_by_prio 1 priority group per priority value. Priorities are determined by callout programs specified as a global, per-con- troller or per-multipath option in the configuration file group_by_node_name 1 priority group per target node name. Target node names are fetched in /sys/class/fc_transport/target*/node_name. Existing maps are not modified. device update only the devmap the path pointed by device is in. device is in the /dev/sdb (as shown by udev in the $DEVNAME variable) or major:minor format. device may alternatively be a multipath mapname SEE ALSO
multipathd(8), multipath.conf(5), kpartx(8), udev(8), dmsetup(8) hotplug(8) AUTHORS
multipath was developed by Christophe Varoqui, <christophe.varoqui@opensvc.com> and others. July 2006 MULTIPATH(8)
Check Out this Related Man Page
MULTIPATHD(8) System Manager's Manual 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 Forground Mode. Don't daemonize, and print all messages to stdout and stderr. -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. -k multipathd will enter interactive mode. From this mode, the available commands can be viewed by entering "help". When you are fin- ished 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/multi- path.conf. list|show blacklist Show the currently used blacklist rules, derived from default values and values specified within the configuration file /etc/multi- path.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. 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 $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 $map Stop monitoring a multipath device. resize map|multipath $map Resizes map $map to the given size switch|switchgroup map $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. 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 quit|exit End interactive session. SEE ALSO
multipath(8) kpartx(8) hotplug(8) AUTHORS
multipathd was developed by Christophe Varoqui, <christophe.varoqui@opensvc.com> and others. Linux Administrator's Manual November 2009 MULTIPATHD(8)