For RAID I would recommend using a minimum of four hard drives, or you'd be better off with them as separate disks. For proper RAID support you should look for a card based on the PCI express bus (x16 ideally, but x4 or x1 if you don't have any spare) because the bandwidth limitations of PCI are too low to support several drives at a decent speed. You also ideally need a hardware RAID solution, as this will allow a contiguous array even if you have to reinstall your OS, and will provide far better performance as your CPU doesn't have to process the data. You should realistically only be looking at RAID1, RAID0+1/1+0/10, RAID5, RAID6 or RAID50. RAID0 is not something I would ever consider due to its poor redundancy. Examples: Individual drives: 2x 500GB drives -> transfer speed low, total space 1TB, no redundancy RAID1: 2x 500GB drives -> total space 500GB, transfer speed low, single drive redundancy RAID5: 4x 500GB drives -> total space 1500GB, transfer speed moderate, single drive redundancy RAID6: 4x 500GB drives -> total space 1TB, transfer speed moderate, double drive redundancy RAID10: 4x 500GB drives -> total space 1TB, transfer speed high, double drive redundancy RAID50: 8x 500GB drives -> total space 3TB, transfer speed high, double drive redundancy Example RAID card: http://www.newegg.com/Product/Product.aspx?Item=N82E16816115029 Ensure the drives you use in the array are identical. It's not essential, but thoroughly recommended.
If you're looking for top of the line, then 3ware is the best (link here). This is overkill for most people, but you'll get the best performance and reliability. Of course, as the price will show, it's not for everybody.
sure ive thought of just buying a raptor but that too gets really pricey if your looking for a large one
which you shouldn't do anyway, as only the smaller (36 or 74GB) Raptors are any good as far as reliability goes.
