So the purpose of Rend, actually… So for us, Netflix as a whole has changed into a N+1 architecture globally. What that means is any member can be served from any region that we have. We operate in three AWS regions, and as the caching layer for the company, we actually do global data replication and it’s partly to support this N+1 architecture.
It’s really expensive though, when you have all of this data that’s stored multiple times in RAM when it’s really only read in one region. So the purpose of this overall project that we called Moneta was to store some of that cold data on disk, and allow the hot data to still be served from RAM as fast as it could be, but the cold data would be in much cheaper storage.
As a part of that now, Rend is the on-box memcached proxy that does… It’s a wire-compatible memcached proxy; our client didn’t change at all, it still uses the same Java memcached client that we were using before. That’s actually sort of the secret sauce of the EVCache product, and it speaks to Rend.