"I've seen a lot of confusion about Linux RAID, so let's clear
that up. Linux software RAID has nothing to do with hardware RAID
controllers. You don't need an add-on controller, and you don't
need the onboard controllers that come on most motherboards. In
fact, the lower-end PCI controllers and virtually all the onboard
controllers are not true hardware controllers at all, but
software-assisted, or fake RAID. There is no advantage to using
these, and many disadvantages. If you have these, make sure they
are disabled."