Hard Disks bound IO is known to be a bottleneck in many high
end applications. Almost 10 years ago I ran into such problem
myself and ended up solving it by replacing hard disks used for
database storage with SSD drives. We paid $125,000 for 6GB
at that time, but it worked and price was Ok, since application
(High end Prepaid Call Platform) payed back for it in a couple
of weeks. SSD drives prices came down since then significantly,
but
this device seems to leap forward in performance x10 on
over today's SSD drives and x1000 over current generation of
disk drives. Interesting times...