| Developer(s) | Junjiro Okajima |
|---|---|
| Full name | Advanced multi layered unification filesystem |
| Introduced | 2006 |
| Features | |
| File system permissions | POSIX |
| Other | |
| Supported operating systems | Linux via third-partykernel module |
| Website | aufs.sourceforge.net |
aufs (short foradvanced multi-layered unification filesystem) implements aunion mount forLinuxfile systems. The name originally stood forAnotherUnionFS until version 2.
Developed byJunjiro Okajima in 2006,[1] aufs is a complete rewrite of the earlierUnionFS. It aimed to improve reliability and performance, but also introduced some new concepts, like writable branch balancing,[2] and other improvements – some of which are now implemented in the UnionFS 2.x branch.
aufs was rejected for merging into mainline Linux. Its code was criticized for being "dense, unreadable, [and] uncommented".[3] Instead,OverlayFS was merged in the Linux kernel.[4][5] After several attempts to merge aufs into mainline kernel, the author has given up.[6]
Aufs is included inDebian "Jessie" (v8) andUbuntu 16.04 out of the box. Debian "Stretch" (v9) does not include aufs anymore, but provides a package aufs-dkms, which auto-compiles the aufs kernel module usingDell'sdkms.
Docker originally used aufs for container filesystem layers. It is still available as one of the storage backends but is deprecated in favour of theoverlay2 backend which usesOverlayFS.[7]
SeveralLinux distributions have chosen aufs as a replacement for UnionFS, including:
