RocketRAID 2314MS is a new PCI Express-based external storage controller card that’s Mac compatible. It costs $199.
The card features a single external mini-Serial Attached SCSI (mini-SAS) interface that can connect up to four SATA II hard drives on its own. But combined with Port Multipliers (PMs), which the card supports, you can have a total of 20 hard drives connected. You can configure those drives in RAID Level 0, 1, 5 or 10 configurations, or use them as a JBOD (Just a Bunch Of Disks) configuration if you prefer.
Features of the card include support for staggered hard drive spinup, hot swap and hot spare support, bad sector reallocation and remapping, quick background initialization for RAIDs, online array roaming, automatic RAID rebuild and more.
The card works on PCIe-equipped Power Mac G5 systems, Mac Pros and Intel Mac Xserve systems. It also supports PCs.