I really don't understand. Knowing the hardware doesn't stop it from failing. There seems to be two approaches here. One, buy really expensive HA hardware. Two,

I really don't understand. Knowing the hardware doesn't stop it from failing. There seems to be two approaches here. One, buy really expensive HA hardware. Two, build software that assumes failure and can handle it. Neither of these guarantee 100% uptime, but you can do the second one on a cloud without knowing the hardware. Side Note: I've done e-commerce, and e-commerce typically makes all of their money around christmas. It seems crazy to me to buy super expensive HA hardware that can handle your peak xmas throughput, and leave it idle for 11 months of the year.