How to configure storage for the best performance of Oracle
Starting in Oracle10g Oracle's storage recommendations is to use Automatic Storage Management (ASM). Oracle also officially recommends using the SAME approach (Stripe And Mirror Everywhere), which is RAID 1+O ( also known as RAID 10 ) with segregation of undo and redo on separate spindles.
Each Area listed above should be a RAID 10 array with as many disks as possible in each array, generally the more disks in each array the better performance.