[ksec]

It is 180 Million divided by 5000 instances, or 36K request per instance.

Honestly not that high of a number from memcached [1] prospective. It could easily handle 10x that even with SSD extstore.

[1] https://memcached.org/blog/nvm-multidisk/

[LINKIWI]

Yeah, 36k per instance (especially on an xlarge or 2xlarge EC2 instance) is well within the serving capacity of memcached. While it depends a lot on the workload profile for a specific cluster, some clusters serve on the order of ~5k/instance while others are as high as ~100k/instance. We've done a lot of experimentation with extstore as well; it certainly eats up more compute cycles on average than an equivalent in-memory only cluster, but is still quite efficient.