I just positively confirmed that you NEED to run a linux kernel with ‘noapic’ like this:
...
kernel /vmlinuz-2.6.17-1.2142_FC4smp ro root=LABEL=/ noapic
...
Omitting noapic resulted in an array that would loose a harddrive for a split second in the very same midplane position after 12 – 14 hours of heavy use. The array state would switch to DEGRADED and it would rebuild for a couple of hours. Never lost any data. Just allot of time in trying to fix hardware that was not broken in the first place.