multipath



MULTIPATH(8)             Linux Administrator’s Manual             MULTIPATH(8)




NAME

       multipath - Device mapper target autoconfig


SYNOPSIS

       multipath   [-v verbosity]   [-d]   [-l]  [-i int]  [-p failover|multi-
       bus|group_by_serial|group_by_prio|group_by_node_name] [-S] [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

       -d     dry run, do not create or update devmaps

       -l     list the current multipath configuration


       -i interval
              multipath target param: polling interval

       -D major:minor
              update only the devmap the path pointed by major:minor is
              in

       -F     flush all the 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-con-
                               troler  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/tar-
                               get*/node_name.

       -S     do  not  send  signal  to  multipathd.  -d  activate this
              silently.

       device update only the devmap the path pointed by device is  in.
              device  is in the /dev/sdb (as shown by udev in the $DEV-
              NAME variable) or major:minor format.  device may  alter-
              natively be a multipath mapname


SEE ALSO

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


AUTHORS

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



                                 February 2004                    MULTIPATH(8)

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