Scale 'out and not 'up'

Scale “out”, not “up”. For data-intensive workloads, a large number of commodity low-end servers (i.e., the scaling “out” approach) is preferred over a small number of high-end servers (i.e., the scaling “up” approach). The latter approach of purchasing symmetric multi-processing (SMP) machines with a large number of processor sockets (dozens, even hundreds) and a large amount of shared memory (hundreds or even thousands of gigabytes) is not effective cost wise, since the costs of such machines do not scale linearly (i.e., a machine with twice as many processors is often significantly more than twice as expensive). On the other hand, the low-end server market overlaps with the high-volume desktop computing market, which has the effect of keeping prices low due to competition, interchangeable components, and economies of scale.