You would know this too if you searched the thread. Search is your friend.
now that it is gone, why not?
Very little of it has to do with the "whale" (almost none actually), since his miners almost immediately switch to way above 512 due to the speed (they were at 1024/2048), plus, as soon as we added the d=xxx param in passwords, he immediately put that on them.
The vardiff change happened when everyone switched from MC. Was just a matter of the server having to keep track of a few hundred miners, and all their recent shares, and mining speeds, and send difficulties out, and then all of a sudden have to handle a few thousand (right now, we're running at about 30k connections/server). Its just too much to keep track of, and saying "nope, its 512" makes the load acceptable
So, PW, was this a temporary measure until your pool's design is improved to handle more load? Or, it became a permanent "fix"?