We used to do this at Amazon in the 00's for onsite hosts. At the time round robin DNS was the fastest way to load balance as even with dedicated load balancers

We used to do this at Amazon in the 00's for onsite hosts. At the time round robin DNS was the fastest way to load balance as even with dedicated load balancers of the time, the latency was a few milliseconds slower. A lot of the decisions didn't make sense to me and seemed to be grandfathered in from the 90's. We had a dedicated DNS host and various other dedicated hosts for various services related to order fulfillment. A batch job would be downloaded in the morning to the order server (app) and split up amongst the symbol scanners which ran basic terminals. To keep latency as low as possible the scanners would dns round robin. I'm not sure how much that helped because the wifi was by far the biggest bottleneck simply for the fact of interference, reflection and so on. With this setup an outage would have no effect the throughput of the warehouse since the batch job was all handled locally. As we moved toward same day shipping of course this was no longer a good solution and we moved to redundant, dedicated fiber and cellular data backup then almost completely remote servers for everything but app servers. So what we were left with was million dollars hvac to cool a quarter rack of hardware and a bunch of redundant onsite tech workers.