INFORMIX & RAID

I am setting up Informix 7.11uc1 on raid. This is the first time I've used a Raid device in setting up Informix so here's my question. I have two separate raid boxes... 18 - 4 gig drives. I understand that I can only use 16 of them because one on each controller is used for parity. Anyway, How can you point rootdbs to a physical drive, logs to another, and then stripe the data/indexes over the rest of the unit? If I group all the drives on one controller as Lun 0 and the other drives as Lun 1 and just slap everything out there I'm not sure whether or not Informix would barf when it tries to run. Performance may not be the greatest in my opinion but since I'm not sure how Raid handles this...I have nothing to base my opinion on. Anyone that's worked with raid can send a reply to edbid @ cobe.com. All replies would be appreciated. I'd like to put rootdbs and logs on separate disks and then stripe out the other dbspaces. Our database is mostly OLTP - about 45 gb with 600-800 users at any one time. Tks in advance Ed edbid@cobe.com