Manual Reference Pages  - MULTIPATH (8)

NAME

multipath - Device mapper target autoconfig

CONTENTS

Synopsis
Description
Options
Notes
Authors

SYNOPSIS

multipath [-v verbosity] [-d] [-h|-l|-ll|-f|-F] [-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
-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

NOTES

a map may be unused if, eg, the file system on it is not mounted or there are no open file descriptors against the device file, as in a raw device.

SEE ALSO

udev(8), dmsetup(8) hotplug(8)

AUTHORS

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


MULTIPATH (8) July 2006
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