Trio is a new way to build file systems that run entirely in user space and take full advantage of fast non-volatile memory (NVM). It separates the core metadata that defines the file system structure from auxiliary metadata that applications can customize for their needs. This split design allows applications to access NVM directly for performance, while still having integrity of the core metadata verified by a trusted system component. Trio includes ArckFS, a general POSIX-like file system, as well as examples of customized application-specific file systems that are faster than previous NVM file systems.

Trio is a userspace NVM file system architecture that decouples file system design, access control, and metadata integrity enforcement. It defines a core state data structure shared between LibFSes and a trusted entity. LibFSes can customize with private auxiliary state while directly accessing NVM. The trusted entity verifies core state integrity when write access transfers between LibFSes. This allows customization while ensuring metadata integrity. Trio includes ArckFS, a POSIX-like FS, and customized FSes that outperform existing NVM file systems.