Q. How can I create mpath devices for partitions under CentOS Linux 5?
A. You need to use tool called kpartx. This is derived from util-linux partx package, which reads partition tables on specified device and create device maps over partitions segments detected. It is called from hotplug upon device maps creation and deletion. This is useful for setting multipath which is used to detect multiple paths to devices for fail-over or performance reasons and coalesces them.
To Setup your multipath type the following command at a shell prompt (login as the root user):
# for d in $(ls /dev/mapper/mpath*); do kpartx -a -v $d ; done