Sprites combine prepared compute environments with storage that survives their active sessions. Fly.io's implementation account says each starts from a standard image, allowing the service to keep empty environments ready. Creation therefore avoids downloading and unpacking a different user-supplied image each time.
Persistent files use a separate mechanism: immutable data chunks live in object storage, while metadata records how to assemble them. Local fast storage serves as a cache. Filesystem checkpoints and restores change that metadata rather than copying the entire disk, which explains how the design supports frequent recovery points alongside retained files.
