I know this area fairly well and the only thing that I see in the numbers that looks surprising (or rather, wrong) is that the disk cache obviously wasn't being flushed after writes.
Which is rather a big deal when you benchmark a persistent kv-store versus a volatile one, don't you think? The persistent one is eventually i/o bound.
Furthermore whatever he is measuring, it is neither tokyo tyrant nor memcache. Memcached doesn't break a sweat doing upwards of 10k ops/sec on moderate hardware, especially when all you're doing is increments. He managed to get 2000/sec out of it.
So again, whatever he's measuring, it's not the "performance of key/value stores". Both the article-title and the linkbait HN title are wrong.
