MULTIPATH(8)

NAME
multipath - Device mapper target autoconfig.

SYNOPSIS
multipath [-v verbosity] [-b bindings_file] [-d] [-h|-l|-ll|-f|-t|-T|-F|-B|-c|-C|-q|-r|-i|-a|-u|-U|-w|-W] [-p failover|multibus|group_by_serial|group_by_prio|group_by_node_name] [-R retries] [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  Display the currently used multipathd configuration.

-T  Display the currently used multipathd configuration, limiting the output to those devices actually present in the system. This can be used a template for creating multipath.conf.

-r  Force devmap reload.

-i  Ignore WWIDs file when processing devices. If find_multipaths strict or find_multipaths no is set in multipath.conf, multipath only considers devices that are listed in the WWIDs file. This option overrides that behavior. For other values of find_multipaths, this option has no effect. See the description of find_multipaths in multipath.conf(5). This option should only be used in rare circumstances.

-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.

-C  Check if a multipath device has usable paths. This can be used to test whether or not I/O on this device is likely to succeed. The command itself doesn't attempt to do I/O on the 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.

-U  Check if the device specified in the program environment is a multipath device with usable paths. See -C.

-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
        One path per priority group.

    multibus
        All paths in one priority group.

    group_by_serial
        One priority group per serial number.

    group_by_prio
        One 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
        One priority group per target node name. Target node names are fetched in /sys/class/fc_transport/target*/node_name.

Existing maps are not modified.

-R retries
    Number of times to retry flushing multipath devices that are in-use. The default is 0.

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/sdX

        •   major:minor

SEE ALSO
multipathd(8), multipath.conf(5), kpartx(8), udev(8), dmsetup(8), hotplug(8).

AUTHORS
multipath-tools was developed by Christophe Varoqui <christophe.varoqui@opensvc.com> and others.