Unionfs: A Stackable Unification File System

This project builds a stackable unification file system, which can appear to merge the contents of several directories (branches), while keeping their physical content separate. Unionfs is useful for unified source tree management, merged contents of split CD-ROM, merged separate software package directories, data grids, and more. Unionfs allows any mix of read-only and read-write branches, as well as insertion and deletion of branches anywhere in the fan-out. To maintain unix semantics, Unionfs handles elimination of duplicates, partial-error conditions, and more. Unionfs is part of the larger FiST project which includes the Wrapfs wrapper stackable file system.

Software Download:

Unionfs releases of kernel code and user-level utilities, as well as snapshots, are available via FTP or HTTP. Full kernel versions patched with Unionfs can be accessed via Git from our git server.

Download Unionfs 2.x with experimental On Disk Format (ODF) support. Read the ODF Design Document.

Unionfs 2.x is maintained in a Git repository. Here are instructions how to check out the latest code with Git.

See list of mirror sites.

Kernel Version Compatibility: