The question that begs is: does he care if he loses all his data if a drive faults (more space cheaper), or does he want it backed up (less space, unless you dump $ into it) safely?
Uhhh... what? I'm not sure what you're talking about, because it doesn't make any sense regarding this specific topic.
Assuming that you use a RAID 5 configuration in each said situation, data integrity wouldn't have a noticable improvement with either decision, unless one set of drives is known for its survivability, but that's not much of a fair assumption.
With RAID 5, the capacity of the member disks doesn't add or remove from the integrety of the array as a whole. You can compose the entire array of 10 GB disks... it doesn't matter. If a single drive in the array fails, it will rebuild itself. If more than one fails before the rebuild is complete, you lose data. The types of disks used in this type of configuration doesn't make
any difference.
Like I already said, the idea of RAID is to create a single storage space made up of several smaller constituents, theoretically reducing the chance of failure (in this specific case. some configurations, like RAID 0, are intended to increase performance while actually significantly decreasing data integrety. others, like RAID 1, are for backup purposes -- the entire drive is mirrored) and usually increasing performance as well.
Oh, and zorm: what type of space are you talking about? I can see where a RAID storage device becomes useful (and even necessary) when data on it is constantly being accessed (like on a server), but unless this is the case, I don't see much of an advantage unless you just need a huge drive to store things on, IE 1 TB+. Also, have you looked into things like NAS units?
Grr... I've edited this post like 5 times. I keep forgetting things. If you do end up going this route, I wouldn't recommend SCSI. With SATA 3.0 GB/s out, I'm not even sure SCSI has a speed advantage.
