Random routing seems okay if you think only about busy servers under light load. However, one of the problems is it creates light servers when under heavy over

Random routing seems okay if you think only about busy servers under light load. However, one of the problems is it creates light servers when under heavy over-all load. Any time a server is idle during a high overall demand period is work opportunity that is irreversibly lost. I made this argument in the single-thread 2-server case here http://www.win-vector.com/blog/2013/02/randomized-algorithms-can-have-bad-deterministic-consequences/ http://www.win-vector.com/blog/2013/02/randomized-algorithms... , but he principle applies much more generally.