Short answer it's a pretty arbitrary cutoff. 16 is the largest number of nodes we've done sufficiently rigorous tests on to be sure that things go smoothly. So

Short answer it's a pretty arbitrary cutoff. 16 is the largest number of nodes we've done sufficiently rigorous tests on to be sure that things go smoothly. So that's the highest number we're comfortable citing on our site. It's a conservative estimate though so you should be fine straying past it. We know of a few things which becoming scalability concerns with a large numbers of machines but we're talking close to 100 machines. These will hopefully be addressed soon.