Installation guide

If the SCSI devices do not appear, ensure that all SAN connections are set up properly.

For further information on the m ultipath command and its output, see Section 5.1, “Multipath

Command Output”, see Section 5.2, “Multipath Queries with multipath Command”, and see

Section 5.3, “Multipath Command Options”.

5. Execute the following command to ensure sure that the multipath daemon starts on bootup:

chkconfig multipathd on

Since the value of user_friendly_name is set to yes in the configuration filea the multipath devices

will be created as /dev/mapper/m pathn. For information on setting the name of the device to an alias

of your choosing, see Chapter 4, The DM-Multipath Configuration File.

3.2. Ignoring Local Disks when Generating Multipath Devices

Some machines have local SCSI cards for their internal disks. DM-Multipath is not recommended for

these devices. The following procedure shows how to modify the multipath configuration file to ignore the

local disks when configuring multipath.

1. Determine which disks are the internal disks and mark them as the ones to blacklist.

In this example, /dev/sda is the internal disk. Note that as originally configured in the default

multipath configuration file, executing the m ultipath -v2 shows the local disk, /dev/sda, in the

multipath map.

For further information on the m ultipath command output, see Section 5.1, “Multipath Command

Output”.

Chapter 3. Setting Up DM-Multipath