NAME

       multipath - Device mapper target autoconfig

SYNOPSIS

       multipath               [-v verbosity]               [-b bindings_file]               [-d]
       [-h|-l|-ll|-f|-t|-F|-B|-c|-q|-r|-i|-a|-u|-w|-W]
       [-p failover|multibus|group_by_serial|group_by_prio|group_by_node_name] [device]

DESCRIPTION

       multipath  is  used  to  detect  and  coalesce multiple paths to devices, for fail-over or
       performance reasons.

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

       -i     ignore wwids file when processing devices

       -B     treat the bindings file as read only

       -b  bindings_file
              set   user_friendly_names    bindings    file    location.     The    default    is
              /etc/multipath/bindings

       -c     check if a block device should be a path in a multipath device

       -q     allow device tables with queue_if_no_path when multipathd is not running

       -a     add the wwid for the specified device to the wwids file

       -u     check  if  the  device  specified  in the program environment should be a path in a
              multipath device.

       -w     remove the wwid for the specified device from the wwids file

       -W     reset the wwids file to only include the current multipath devices

       -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-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.

              Existing maps are not modified.

       device update only the devmap specified by device, which is either:

                   •      a devmap name

                   •      a  path  associated  with the desired devmap; the path may be in one of
                          the following formats:

                               •      /dev/sdb

                               •      major:minor

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)