A few months ago we published a blog post that talked about our servers doing 1 million tcp connections on a single box: http://blog.whatsapp.com/?p=170

Today we have an update for those keeping score at home: we are now able to easily push our systems to over 2 million tcp connections!


jkb@c123$ sysctl kern.ipc.numopensockets
kern.ipc.numopensockets: 2277845

Very impressive numbers, if only in exploiting the awesome hardware they have available. I wish I could run on dual hex-cores with 96GB RAM ;-) I wonder if they even need two boxes with a setup like this for connection concentration.