A buddy is looking to get a raid as they are now using separate drives connected to a linux box. I'm relative tech savvy and know how they basically work but could use a little help on deciding what's best. The application that will be accessing the data is a stats package so we don't need super speedy access, redundancy and size are the main objectives. I was looking at Raid 5 but I read some comments about how it's not good to use with very large drives; something along the lines of if one drive goes bad and then during the rebuild you're bound to get a write error because of the nature of large disks then the whole array will go tits up. The sysadmin suggested raid6 but I the hardware seems to be astranomical for this. This is what he suggested: The smallest RAID that makes sense for purchase today is a 12-BAY Infortrend with 12 1TB drives for a total of 12TB. However, because of format'ing and the RAID-6 technology, you really only end up with about 9TB of useable space in this type of RAID. The Infortrend model is a great RAID vendor. I have attached 4 quotes I just recently obtained to provide you an idea on pricing for a variety of sized RAIDs from ~9TB useable to ~26TB useable. These quotes are as follows: 2U 12-Bay 1TB drives (12TB/~9TB usable): $4750.00 2U 12-Bay 2TB drives (24TB/~18TB usable): $6406.00 3U 16-Bay 1TB drives (16TB/~13TB usable): $6305.00 3U 16-Bay 2TB drives (32TB/~26TB usable): $8513.00 Seems like these things are pretty pricey. What's wrong with this? http://eshop.macsales.com/item/Other World Computing/RP936QE8.0T/ So in summary, do we really need to go with Raid6 rather than Raid5 and, why is the hardware so pricey!