[Oracle Linux 6.x] The Oracle Linux 6.x operating system does not automatically load the device-mapper driver by default upon restarting the multipathd service, so it may be necessary to load the driver manually before installing Oracle FS Path Manager (FSPM).
The multipath driver must always be loaded before FSPM is installed.
# DM multipath kernel driver not loaded
mpathconf --with_module y
Refer to the mpathconf man pages for an explanation.
# modprobe dm_multipath
The first method is recommended.