Informix on IBM SAN?

Hello! Does anyone have experience running Informix (or any database, for that matter) on the new IBM SAN (storage area network) equipment? My company is proposing that we move our Informix database tables to SAN, and I've got some concerns. Seeing as these new devices abstract the disks into logical volumes, and are RAID underneath, how do you deal with issues such as table fragmentation, placement on disk (i.e. inner tracks, center tracks) etc? You won't know which disk the tables are on. Or, are these new disk systems just so fast, and so sweet, that I no longer have to think (worry) about such things? That's what the hardware guys are telling me, but it sounds too good to be true. Thanks in advance. Doug