The story of my journey through time and code to implementing ZSTD compression in OpenZFS on FreeBSD. Follow a novice developer through the initial naive attempt to add support for a new compression algorithm to ZFS, then through successive improvements and new stumbling blocks to ultimately arrive at a finished product. What is ZSTD, and why might I want to use it First attempt Allocating memory in the kernel is harder than it looks Ohh, you have to free that memory when you are finished it it..., what a scam The first prototype Alignment is a thing C is hard First working prototype Matt Ahrens pokes holes in your dreams Don't steal from future generations of ZFS You forgot about the L2ARC Getting it committed Conclusions