DNS Caching

I really love watching the statistics as one makes a change for the better, and collecting the visualistaions is a bit of a hobby for me.

DNS Caching connections

This is the graph of active connections on one of our edge appliances. It carries all client internet traffic and also load balances DNS resolution for clients. It was an incredible drop in traffic - over half the active connections on the appliance - and the response time went from ~150ms to ~1ms for repeat requests.

All it took? Turning on DNS caching. Every resource utilisation graph dropped. Instead of having to track relatively long-lived connections, and hang around waiting for the upstream resolvers, it was responding from memory and could get back to idling faster.

I wish we had power utilisation graphs, it’d be interesting to see if there was any noticeable change :)