We have a sharded cluster where each shard has a 5-node replica set spread across 5 physical data centers. Our
mongos instances are located on an app servers and can have 150ms latency because they are on the other side of the planet. I stumbled across
--tcpFastOpenServer and thought it could significantly reduce connection setup latency while also reducing the number of needed pooled connections (since creating a new connection wouldn’t require a 3-way handshake).
Has anyone here turned this setting on? If so, do you have any data or anecdotes of how well it worked? Anyone have any unexpected negative results? I haven’t seen much on the forums discussing this.