XOR Media

Useful Latency Numbers

I ran across this gist on Hacker News which has a quick rundown of the latencies of various operations. It’s nothing earth shattering, but if you compare the intra-data center round-trip (0.5ms) to reading 1MB of data from disk (20ms) you can pretty quickly see why systems like memcached work so well even after adding the overhead of reading from memory (0.25ms) and some time for the sending and receiving of the request. Summed up the memcached response is often back in a few ms, nearly an order of magnitude faster than reading from local disk.