There are a number of very large bottlenecks in MongoDB, and one of the worst is the mongos process. I can't run more than 100 processes on a server talking to

There are a number of very large bottlenecks in MongoDB, and one of the worst is the mongos process. I can't run more than 100 processes on a server talking to a mongos process, because any more than that, mongos uses 70% of the CPU power on a 32-core box. 70% of all CPU for database transaction overhead! After that, it simply stops working. The next one is the insane 20K connection limit per mongod process that is hardcoded into the binary. When asked about it, 10gen says they just decided years ago that that was the limit because no one would ever have more than 20GB in a server. So, I can't just run more mongos processes on other boxes - it hits the 20K limit. I could go on but the point is, MongoDB is really badly designed.