Three engineers, at various points, each took their own approach to adding Rust to a C codebase, each being more and more ambitious. I initially just wanted to replace the server’s networking and event loop with an equally fast Rust implementation. We’d reuse many core components that were in C and just call into them from Rust. Surely it wouldn’t be that much code… Pelikan is Twitter’s open source and modular framework for in-memory caching, allowing us to replace Memcached and Redis forks with a single codebase and achieve better performance. At Twitter, we operate hundreds of cache clusters storing hundreds of terabytes of small objects in memory. In-memory caching is critical, and demands performance, reliability, and efficiency. In this talk, I share my adventures in working on Pelikan and how rewriting it in Rust can be more than just a meme.