The only way you're going to make use of old, mismatched equipment in a shared video editing environment is if you're editing standard def DV based projects. Since it's only about 3.5MB/sec per stream, if you setup a system that's capable of 30-40MB/sec of sustained throughput, it will probably work ok.
Anything else just flat out isn't going to work in any sort of reliable, seamless way when it comes to video....especially anything HD.
There are half a dozen affordable, turn-key solutions out there that don't require third-party SAN management software or any sort of specialized setup. Old drives, ethernet switches, HBAs etc.... regardless of how fast you think they are, are likely not going to give you the throughput needed to work reliably.
But you can certainly try! A better route would be to use that equipment to build a RAID 1 or 6 based backup system (if the drives are only a couple years old). If the drives are 3 years old or older, you're asking for trouble using them for anything critical, unless you have redundant backup in place (either a version of RAID that mirrors or mutliple backup targets).
That's just my $.02.
Chris Blair
Magnetic Image, Inc.
Evansville, IN
http://www.videomi.com
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