MAN page from Mandriva 2009 multipath-tools-0.4.8-4mdv2009.0.i586.rpm

MULTIPATH.CONF

Section: File Formats (5)
Updated: 30 November 2006
Index

NAME

multipath.conf - multipath daemon configuration file

DESCRIPTION

multipath.confis the configuration file for the multipath daemon. It is used tooverwrite the built-in configuration table of multipathd.Any line whose first non-white-space character is a '#' is considereda comment line. Empty lines are ignored.

SYNTAX

The configuration file contains entries of the form:

<section> {<attribute> <value>...<subsection> {<attribute> <value>...
}
}

Each section contains one or more attributes or subsections. Therecognized keywords for attributes or subsections depend on thesection in which they occor.

The following section keywords are recognized:

defaults: This section defines default values for attributes which are usedwhenever no specific setting is given.
blacklist: This section defines which devices should be excluded from themultipath topology discovery.
blacklist_exceptions: This section defines which devices should be included in themultipath topology discovery, despite being listed in theblacklistsection.
multipaths: This section defines the multipath topologies. They are indexed by aWorld Wide Identifier(wwid), which is the result of thegetuid_callout program.
devices: This section defines the device-specific settings.

defaults section

Thedefaultssection recognizes the following keywords:

polling_interval

interval between two path checks in seconds; default is5

udev_dir

directory where udev creates its device nodes; default is/dev

selector

The default path selector algorithm to use; they are offered by thekernel multipath target. The only currently implemented isround-robin 0

path_grouping_policy

The default path grouping policy to apply to unspecifiedmultipaths. Possible values are

failover: 1 path per priority group
multibus: all paths in 1 priority group
group_by_serial: 1 priority group per serial number
group_by_prio: 1 priority group per priority value. Priorities are determined bycallout programs specified as a global, per-controller orper-multipath option in the configuration file.
group_by_node_name: 1 priority group per target node name. Target node names are fetchedin /sys/class/fc_transport/target*/node_name.
Default value is multibus.

getuid_callout

The default program and args to callout to obtain a unique pathidentifier. Should be specified with an absolute path. Default valueis/lib/udev/scsi_id -g -u -s

prio_callout

The default program and args to callout to obtain a path priorityvalue. The specified program will be executed and should return anumeric value specifying the relative priority of this path. Highernumber have a higher priority. A '%n' in the command line will be expandedto the device name, a '%b' will be expanded to the device number inmajor:minorformat.noneis a valid value. Currently the following path priority programs areimplemented:

mpath_prio_emc /dev/%n: Generate the path priority for EMC arrays
mpath_prio_alua /dev/%n: Generate the path priority based on the SCSI-3 ALUA settings.
mpath_prio_netapp /dev/%n: Generate the path priority for NetApp arrays.
mpath_prio_rdac /dev/%n: Generate the path priority for LSI/Engenio RDAC controller.
mpath_prio_hp_sw /dev/%n: Generate the path priority for Compaq/HP controller inactive/standby mode.
mpath_prio_hds_modular %b: Generate the path priority for Hitachi HDS Modular storage arrays.
Default value is none.

features

Specify any device-mapper features to be used. The most common ofthese features is1 queue_if_no_path Note that this can also be set via theno_path_retrykeyword.

path_checker

The default method used to determine the paths' state. Possible valuesare

readsector0: Read the first sector of the device
tur: Issue aTEST UNIT READYcommand to the device.
emc_clariion: Query the EMC Clariion specific EVPD page 0xC0 to determine the pathstate.
hp_sw: Check the path state for HP storage arrays with Active/Standby firmware.
rdac: Check the path state for LSI/Engenio RDAC storage controller.
directio: Read the first sector with direct I/O.
Default value is readsector0.

failback

Tell the daemon to manage path group failback, or not to. 0 orimmediatemeans immediate failback, values >0 means deferred failback (inseconds).manualmeans no failback. Default value ismanual

rr_min_io

The number of IO to route to a path before switching to the next inthe same path group. Default is1000

rr_weight

If set to priorities the multipath configurator will assignpath weights as "path prio * rr_min_io". Possible values areprioritiesoruniformuniform

no_path_retry

Specify the number of retries until disable queueing, orfailfor immediate failure (no queueing),queuefor never stop queueing. Default is 0.

user_friendly_names

If set to yes, using the bindings file/var/lib/multipath/bindingsto assign a persistent and unique alias to the multipath, in the form of mpath<n>.If set to nouse the WWID as the alias. In either case this be willbe overriden by any specific aliases in the multipaths section.Default isno

blacklist section

Theblacklistsection is used to exclude specific device from inclusion in themultipath topology. It is most commonly used to exclude local disks orLUNs for the array controller.

The following keywords are recognized:

wwid: The World Wide Identification of a device.
devnode: Regular expression of the device nodes to be excluded.
device: Subsection for the device description. This subsection recognizes thevendorandproductkeywords. For a full description of these keywords please see thedevicessection description.

blacklist_exceptions section

Theblacklist_exceptionssection is used to revert the actions of theblacklistsection, ie to include specific device in themultipath topology. This allows to selectively include devices whichwould normally be excluded via theblacklistsection.

The following keywords are recognized:

wwid: The World Wide Identification of a device.
devnode: Regular expression of the device nodes to be excluded.
device: Subsection for the device description. This subsection recognizes thevendorandproductkeywords. For a full description of these keywords please see thedevicessection description.

multipaths section

The only recognized attribute for themultipathssection is themultipathsubsection.

Themultipathsubsection recognizes the following attributes:

wwid: Index of the container. Mandatory for this subsection.
alias: (Optional) symbolic name for the multipath map.

The following attributes are optional; if not set the default valuesare taken from thedefaultssection:

path_grouping_policy
path_checker
path_selector
failback
no_path_retry
rr_min_io

devices section

The only recognized attribute for thedevicessection is thedevicesubsection.

Thedevicesubsection recognizes the following attributes:

vendor

(Mandatory) Vendor identifier

product

(Mandatory) Product identifier

product_blacklist

Product strings to blacklist for this vendor

hardware_handler

(Optional) The hardware handler to use for this device type.The following hardware handler are implemented:

1 emc: Hardware handler for EMC storage arrays.