The Tornado Cache (FIFO) hasn't really been an issue as an eviction algorithm. Most of our caches are sized to hold over a weeks (most over a months) worth of

The Tornado Cache (FIFO) hasn't really been an issue as an eviction algorithm. Most of our caches are sized to hold over a weeks (most over a months) worth of objects in cache. Most objects/traffic is temporal in nature. The popular images and videos are normally only popular for a certain time period. We have looked at not evicting objects on disk if they are in the RAM cache and that has a LRU like eviction algorithm (really it is a CFLUS). Doing this would help in not evicting really popular objects. FIFO has advantages over LRU for disks. It is very efficient with writes since they are all sequential. We use rotational disks when building out very large second tier caches. There are other things to consider when looking at cache in a proxy server. How many bytes does the in memory index take per object in cache (for ATS 10 bytes and that is extremely efficient). Also, does the cache use the filesystem and/or use sendfile for HTTP (like NGiNX), but can't use sendfile when using HTTPS or HTTP/2. Netflix is experience this pain when moving to HTTPS with NGiNX. Every proxy server some advantage, easy of use, well supported APIs, flexible configuration, dynamic loadable modules, HTTP specification compliance, HTTP/2 support, TLS support, performance, etc. It really depends on what you are looking for when choosing a proxy server.