I see, so your idea is to reduce the number of geographical points to increase hit rate? Because if you have “one” location aka everything on one server, that’s a perfect hit rate.
I would imagine this comes down to knowing your specific audience, and where they are – so metrics would need to be gathered first about which geographical CDN points are being hit, then consolidate to the most used?
If you want a higher hit rate then your choices are 1) fewer PoPs or 2) longer retention. The first choice is going to make the experience worse for some clients, the second is going to cost more money (if it’s even available).
This is exactly what you need to find out. What are your misses and where are they coming from?
The 5 PoPs closest to the majority of our traffic are averaging about low 80s% hit cache rate, whereas the other ones with more sporadic traffic- the lower the traffic is, the lower the hit rate, sometimes below 50%. That’s when I think consolidating the PoPs can bring the hit rate up so the CDN doesn’t always have to go back to the origin to fetch, which, speedwise is worse than just serving from the origin. Its a tradeoff between additional latency with PoPs located farther away, and reduced latency from increased cache rate at the PoP.
Longer retention is tougher to solve. That’s the lever that can bring up the hit rate for the high traffic PoPs, and I don’t necessarily have a solution for that, yet.
I am curious about others’ experience- Does high-70s% and low-80s% cache rate for user-uploaded assets feel low/ about right?
