this came to mind when it was mentioned that the main db server is starting to hit a wall. i know that some of the services have been offloaded already... but the future is coming quickly. i still adamently believe that multiple db servers handling the main load would be best way to go, but it would require a partial redesign and brad hasnt mentioned what he thinks of doing so, at least that i recall.
anyway, i have one more statement in regards to the database server/raid choice... and it follows:
keep in mind that the sustained server dataload will be no greater than the speed of the PCI bus or the limit between the north and south bridges (whichever is less). i believe the alpha had a 64 bit pci bus (was it 33 or 66mhz?)... but is the card 32 bit? if so, you will still be limited to 133MB/s transfer at 33mhz. keep this in mind since 5 disks doing 30MB/s sustained (very realistic for a heavy hit on raid 0) would easily saturate this bus.
things to look at... is the raid controller interface pci based? is it 64 bit? is the servers pci bus 33mhz? 66mhz? what is the connection between the north and south bridges? is it just the pci bus? is it a 266MB/s link instead? does it use something like serverworks' IMB?
just thoughts... i didnt feel like digging for the thread on the alpha to find the specs again... but i think this is all applicable still.