| MULTIPATH(8) | Linux Administrator's Manual | MULTIPATH(8) |
NAME¶
multipath - Device mapper target autoconfig
SYNOPSIS¶
multipath [-v verbosity] [-d] [-h|-l|-ll|-f|-F|-B|-a|-w|-W] [-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
- -r
- force multipath to reload the device maps
- -B
- treat the bindings file as read only
- -c
- check if the specified path device is or should be multipathed
- -a
- add the wwid for the specified device to the wwids file
- -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 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.
| July 2006 |