HP StorageWorks Device Mapper Multipath Enablement Kit for HP StorageWorks Disk Arrays installation and reference guide (AA-RW8RE-TE, June 2009)

3 Configuring DM Multipath

This chapter addresses the following topics:

• Using /etc/multipath.conf File

• Setting up Device Mapper Multipath daemon

Using /etc/multipath.conf File

DM Multipath kit includes a template file with the recommended configuration for HP supported arrays.

To configure DM Multipath, edit the /etc/multipath.conf configuration file. This file also enables you

to customize DM Multipath for a variety of SAN storage subsystems.

The /etc/multipath.conf file consists of the following sections to configure the attributes of a

Multipath device:

• System defaults (defaults)

• Black-listed devices (devnode_blacklist/blacklist)

• Storage array model settings (devices)

• Multipath device settings (multipaths)

• Blacklist exceptions (blacklist_exceptions)

The defaults section defines default values for attributes which are used whenever required setting

is unavailable. The blacklist section defines which devices should be excluded from the multipath

topology discovery. The blacklist_exceptions section defines which devices should be included

in the multipath topology discovery, despite being listed in the blacklist section. The multipaths

section defines the multipath topologies. They are indexed by a World Wide Identifier (wwid). The

devices section defines the device-specific settings based on vendor and product values.

Table 2 lists the important attributes of HP supported arrays.

Table 2 HP Recommended configuration parameters

Supported ValuesDescriptionAttribute

multibus: All valid paths in one

priority group

group_by_prio: One priority group

per path priority value

weightedpath <hbtl|devname>

<prio2>: Provides static load

balancing policy by assigning

higher priority to the preferred path

failover: One path per priority

group

Used for applying the policy to the

multipath device hosted by this

storage controller

path_grouping_policy

tur

Used for determining the state of

the path

path_checker

Device Mapper Multipath Enablement Kit for HP StorageWorks Disk Arrays installation and reference

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