Memcached Results, Continued
My last post end with a few questions. I realized as I was writing them that I had an easy way to answer one of them — “How much (if any) would response times improve by moving memcached to servers that were not overloaded serving web requests?”.
This graph is similar to this one from my previous post, but adds a fourth server to the memcached pool: ist-wp-app-prod04. When I ran these benchmarks, app-prod04 was not yet accepting web requests, and as such is representative of response times we might see if the memcached instance was not running on a busy app server.
Response times from app-prod04 are nearly 50% quicker than the other remote instances (app-prod02 and 03). Again the benchmark was run from ist-wp-app-prod01, so response times from that instance are still (understandably) the quickest.
Seems like a good argument for moving memcached off of the app servers…