MULTIPATH(8)

NAME

multipath - Device mapper target autoconfig

multipath  [-v verbosity]  [-d]  [-h|-l|-ll|-f|-F]  [-p failover|multi-
bus|group_by_serial|group_by_prio|group_by_node_name] [device]

multipath is used to detect multiple paths to devices for fail-over or performance reasons and coalesces them

-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 informa: tion (sysfs, the device mapper, path checkers ...)
-f flush a multipath device map specified as parameter, if unused
-F flush all unused multipath device maps
-p policy: force maps to 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-controller 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.
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

multipath was developed by Christophe Varoqui, <christophe.varoqui@free.fr> and others.