The Dm-Multipath Configuration File; Configuration File Overview - Red Hat ENTERPRISE LINUX 5 DM MULTIPATH Configuration And Administration Manual

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Chapter 4.

The DM-Multipath Configuration File

By default, DM-Multipath provides configuration values for the most common uses of multipathing.

In addition, DM-Multipath includes support for the most common storage arrays that support DM-

Multipath. The default configuration values and the supported devices can be found in the /usr/

share/doc/device-mapper-multipath-0.4.7/multipath.conf.defaults file.

You can override the default configuration values for DM-Multipath by editing the /etc/

multipath.conf configuration file. If necessary, you can also add a storage array that is not

supported by default to the configuration file. This chapter provides information on parsing and

modifying the multipath.conf file. It contains sections on the following topics:

• Configuration file blacklist

• Configuration file defaults

• Configuration file multipaths

• Configuration file devices

In the multipath configuration file, you need to specify only the sections that you need

for your configuration, or that you wish to change from the default values specified in the

multipath.conf.defaults file. If there are sections of the file that are not relevant to your

environment or for which you do not need to override the default values, you can leave them

commented out, as they are in the initial file.

The configuration file allows regular expression description syntax.

An annotated version of the configuration file can be found in /usr/share/doc/device-mapper-

multipathd-0.4.7/multipath.conf.annotated.

4.1. Configuration File Overview

The multipath configuration file is divided into the following sections:

blacklist

Listing of specific devices that will not be considered for multipath. By default all devices are

blacklisted. Usually the default blacklist section is commented out.

blacklist_exceptions

Listing of multipath candidates that would otherwise be blacklisted according to the parameters of

the blacklist section.

defaults

General default settings for DM-Multipath.

multipaths

Settings for the characteristics of individual multipath devices. These values overwrite what is

specified in the defaults and devices sections of the configuration file.

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