The other day, while perusing a tech post, I stumbled upon S3 FIFO, a method claiming to outperform LRU (Least Recently Used) in terms of cache miss ratio. Intriguingly, notable companies like RedPandas, Rising Wave, and Cloudflare have already implemented it in various capacities. This piqued my interest. At Datadog, we rely heavily on caches, so I knew I had to put S3 FIFO to the test, or at least, make sure I understood its core ideas.