GoKawiilFly.io replaces custom JuiceFS setup with new Sprites Block Device filesystem
Fly.io has introduced the Sprites Block Device (SBD), a new filesystem replacing the modified JuiceFS system it built at launch for its Sprites product. The original setup used a rewritten SQLite metadata backend kept durable with Litestream, storing a single 100GB disk image mounted as a loop device backed by object storage. SBD keeps the same core design—object storage as the root of a Sprite's disk so it can sleep and wake across servers—but replaces the custom tooling with a simpler, more reliable implementation.