I avoided hardware RAID this time around, because it wants drives of all of the same size and doesn't support drive-spindown, which saves power, and reduces heat and noise. disParity has worked great as a simple software RAID solution, but is very slow when run across 26 drives on expanders, as one might expect.
So, how to move forward? Finding the answer turned-out to be more time-consuming, and mind-confusing, than expected.
After much research, internal dialog, annoying of friends, and weighing of pros/cons, I've come up with what I think is a workable and cost-effective solution.
I'm switching to Serial-Attached SCSI (SAS), now that I understand it better, and reducing those 24 cables to 1. I'll have to live with the risk of bitrot, thanks to Microsoft's inability to develop a new filesystem, and keep everything spinning at all times.
This involves the purchase of a new chassis that includes a backplane to minimize cabling. I've chosen the SuperMicro 846E16-R1200B, which has 24 drive bays runnable through a single SFF-8087 cable. My SATA 2 drive interfaces will only produce a 1.2GB/s maximum in this configuration, but that's perfectly livable for now.
The SAS controller I've chosen also has an external SFF-8088 connection, so adding a second 24-bay chassis (sans motherboard & CPU) will be trivial.
I will likely run two RAID-6 arrays consisting of 24-drives each. Since I don't write data often, that should prove reliable enough. *knocks wood* Plus, it makes it easier to downsize and migrate as 4TB drives become available.
So, my new system will consist of:
Chassis: SuperMicro 846E16-R1200B
CPU: Intel Core i7-980
Mobo: Asus Rampage III Extreme
RAM: 12GB Crucial DDR3
Controller: LSI MegaRAID SAS 9280-4i4e
Video: GeForce 470 (aging, but waiting for a new generation)
Drives: 26+ WD 2TB EURS (may not play nice in a RAID?)
All of which is sitting inside my new Silence Case Attenuation Enclosure
PS: After planning-out how to migrate my data to the new system, I've ordered 6 new drives, for a total of 32, resulting in a total of 5 "capacity expansions" (RAID rebuilds). I'll keep my old Norco running with 8 drives in a RAID-5 (using my old 3Ware controller) until those run out of space.
PPS: ZFS is still neat, but requires gobs of RAM to work efficiently with a 50+ TB array.