For people searching for performance benchmarks like me, here are the numbers I dug around from the post ( http://geo.bitnames.com)

If you need less than 200 DNS lookups per second per DNS server the Perl version is fine and might be a little easier to setup. The Go version is much faster (in prodution we've seen it do 5-6000 requests a second on commodity hardware and even virtual servers).

Is 6000 rps a high number for a DNS server? Let me do a back of the envelope calculation: one simple dns request (assuming udp here) response msg size is 100bytes, 6000rps x 100bytes /1024/1024 x 8 = 4.69mbps. Even we consider the request msg size is equal to that of response msg, the throughput is still 9.38mbps, far from saturating the network pipe. It sounds to me there is still space for improvement.