One problem encountered when setting your RAID storage system is getting mutiple arrays to work together and still have good transfer rates and control. A RAID controller card such as this one gives you four eSATA ports.
This card is compatible with both PCI-X and PCI bus connections and will support RAID 0, 1, 0+1, JBOD, and RAID5. The firmware is upgradeable and if you use SiI3726 and SiI4726 SATA Port Multipliers you can reach even more connections and higher transfer speeds.
Compatible with the majority of operating systems, this card will help you achieve superfact transfers (up to 3Gb/second) and will wirth with any Serial ATA drive.