Setting Up Dm-Multipath - Red Hat DEVICE-MAPPER MULTIPATH 5.2 Configuration And Administration Manual

Chapter 3.

Setting Up DM-Multipath

This chapter provides step-by-step example procedures for configuring DM-Multipath. It
includes the following procedures:
• Basic DM-Multipath setup
• Ignoring local disks
• Adding more devices to the configuration file
1. Setting Up DM-Multipath
Before setting up DM-Multipath on your system, ensure that your system has been updated and
includes the
device-mapper-multipath
Use the following procedure to set up DM-Multipath for a basic failover configuration.
1. Edit the
/etc/multipath.conf
file. This section of the configuration file, in its initial state, blacklists all devices. You must
comment it out to enable multipathing.
blacklist {
devnode "*"
}
After commenting out those lines, this section appears as follows.
# blacklist {
# devnode "*"
# }
2. The default settings for DM-Multipath are compiled in to the system and do not need to be
explicitly set in the
/etc/multipath.conf
The default value of
not need to change the default value. For information on changing the values in the
configuration file to something other than the defaults, see
Configuration File.
The initial defaults section of the configuration file configures your system that the names of
the multipath devices are of the form
devices would be aliased to the WWID of the device.
package.
file by commenting out the following lines at the top of the
path_grouping_policy
mpathn
file.
is set to , so in this example you do
failover
Chapter 4, The DM-Multipath
; without this setting, the names of the multipath
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