The Tornado Cache (FIFO) hasn&#x27;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&#x2F;traffic is temporal in nature.  The popular images and videos are normally only popular for a certain time period.<p>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.<p>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.<p>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 <i>extremely</i> efficient).  Also, does the cache use the filesystem and&#x2F;or use sendfile for HTTP (like NGiNX), but can&#x27;t use sendfile when using HTTPS or HTTP&#x2F;2.  Netflix is experience this pain when moving to HTTPS with NGiNX.<p>Every proxy server some advantage, easy of use, well supported APIs, flexible configuration, dynamic loadable modules, HTTP specification compliance, HTTP&#x2F;2 support, TLS support, performance, etc.  It really depends on what you are looking for when choosing a proxy server.