tl;dr: Every time you build, pull or destroy a Docker container, you are using a storage driver. Current storage drivers like Device Mapper, AUFS, and Overlay2 implement container behavior using file systems designed to run a full OS. We are open-sourcing a file system that is purpose-built for the container lifecycle. We call this new file system Layer Cloning File System (LCFS). Because it is designed only for containers, it is up to 2.5x faster to build an image and up to almost 2x faster to pull an image. We're looking forward to working with the container community to improve and expand this new tool. Layer Cloning FileSystem (LCFS) is a new filesystem purpose-built to be a Docker storage driver. All Docker images are constructed of layers using storage drivers (graph drivers) like AUFS, OverlayFS, and Device Mapper. As a design principle, LCFS focuses on layers as the first-class citizen. The LCFS filesystem operates directly on top of block devices, as opposed to merging separate filesystems. Thereby, LCFS aims to directly manage at the container image’s layer level, eliminate the overhead of having a second filesystem that then is merged, and to optimize for density.