You set up multipath with the mpathconf utility, which creates the multipath configuration file /etc/multipath.conf.

• If the /etc/multipath.conf file already exists, the mpathconf utility will edit it.
• If the /etc/multipath.conf file does not exist, the mpathconf utility will use the /usr/share/doc/device-mapper-multipath-0.4.9/multipath.conf file as the starting file.
• If the /usr/share/doc/device-mapper-multipath-0.4.9/multipath.conf file does not exist the mpathconf utility will create the /etc/multipath.conf file from scratch.

If you do not need to edit the /etc/multipath.conf file, you can set up DM-Multipath for a basic failover configuration by running the following command. This command enables the multipath configuration file and starts the multipathd daemon.

# mpathconf --enable --with_multipathd y

If you need to edit the /etc/multipath.conf file before starting the multipathd daemon. use the following procedure to set up DM-Multipath for a basic failover configuration. Run the mpathconf command with the –enable option specified:

# mpathconf --enable

# mpathconf --help
usage: /sbin/mpathconf <command>

Commands:
Enable: --enable 
Disable: --disable
Set user_friendly_names (Default n): --user_friendly_names <y|n>
Set path_grouping_policy (Default n): --find_multipaths <y|n> 
Load the dm-multipath modules on enable (Default y): --with_module  <y|n>
start/stop/reload multipathd (Default n): --with_multipathd  <y|n>
chkconfig on/off multipathd (Default y): --with_chkconfig  <y|n>

You can change them with the mpathconf command