Re: Predicting Read/Write Latency as a Function of Total Requests & Cluster Size

The theoretical answer involves Little's Law (*L=λW*). But the practical experience is, as you say, dependent on a fair number of factors. We wrote a recent blog

Re: Predicting Read/Write Latency as a Function of Total Requests & Cluster Size

Latency SLAs are very much *not* Cassandra’s sweet spot, scaling throughput and storage is more where C*’s strengths shine. If you want just median latency you’ll find things a bit more amenable to modeling, but not if you have 2 nines and particularly not 3 nines SLA expectations. Basically,