INFORMIX & RAID Help

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 s ince 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