"Twitter's problems cannot be solved in a massive scale
out distributed systems manner. When you are dealing with systems
that are hitting a live database and performing millions of row
inserts at any given time, you are going to go beyond the limits of
what off-the-shelf client/server hardware can accomplish.
"Before I joined IBM in September of 2007, I had just completed
a project for a large government agency that needed a system that
could accomplish approximately 5,500 database row inserts and reads
per second, or approximately 18 million transactions per week. And
as a customer requirement, we had to do it with COMMODITY HARDWARE.
Read as, Intel Chips and Linux.
"The heart of the "beast", as those of us referred to it, was
comprised of 4 Unisys ES7000-based Oracle 10g RAC nodes, each using
256GB of RAM and sixteen dual-core Intel Xeon processors, and the
most sophisticated, high-performance Cisco 10Gbps Ethernet
switching that money could buy which was available between all the
main clustered and load balanced tiers of the system -- Web, J2EE
Application Servers, Messaging Queue and Database."