Okay, sorry, I'll type more slowly. :-)
I'm curious about something. The computing requirements for RAID-5 are quite modest; you just XOR all the blocks in a stripe and write that out as the stripe's parity block. Disk drives are so slow relative to even low end embedded CPUs that software RAID performs just fine.
So why do you need a special RAID controller chip inside the SMARTSTOR? I've used Linux software RAID for years and the CPU loading is way down in the noise. The CPU cost of doing the XOR is nil compared to the network stack, interrupt handlers, disk drivers, etc. So why not just do it all in software?
I may be out of date, but it's been my understanding that most "RAID controller" cards are what the Linux RAID developers call "fakeraid" -- ordinary non-RAID controllers with software RAID in the device driver or ROM BIOS. I presume that's not what you're using.
Since I knew your box ran Linux, I had really hoped that it used Linux software RAID and be accessible to standard Linux admin commands. I am concerned that if you are using a proprietary RAID format and my box should fail, I might not be able to read my drives on anything other than another SMARTSTOR. My data would be inaccessible until I get a new box -- IF a new box is still available. Is this true? The Linux software RAID format is very well documented so I know I will always be able to recover my data long after my vanilla SATA controllers have become completely obsolete.
I researched hardware vs software RAID before I built my existing Linux RAID server. I could see only one real advantage to hardware RAID for Linux -- battery backed RAM that could keep track of disk I/O in process when the power fails to ensure that the disk parity blocks are kept up to date when the system is rebooted. With software RAID you may have to run a utility to walk through the stripes and check or regenerate the parity blocks.
Because the SMARTSTOR and similar boxes are dedicated RAID servers and are small enough to be plugged into a UPS, theoretically it should provide very good data integrity even if the SMARTSTOR uses software RAID internally. In other words, I just don't see the point of doing hardware RAID inside the SMARTSTOR.
What I really want in any RAID server are "dumb" disk controllers fast enough to keep all the drives busy and to implement command queueing to let the drive firmware optimize the order in which it services I/O requests.
Otherwise I think there's far more performance to be gained with better algorithms, e.g., looking for opportunities to defer parity block generation so that fewer need be done, than by putting RAID into the hardware controller.
It certainly does seem that my best bet is to put my drives into a 4-drive bay on a small Linux system configured to do software RAID, and to sell the SMARTSTOR on eBay I am disappointed, though, because the SMARTSTOR's form factor is really quite nice.