Aufs

Not to be confused with AUFS.
aufs
Developer(s)Junjiro Okajima
Full nameAdvanced multi layered unification filesystem
Introduced2006
Features
File system
permissions		POSIX
Other
Supported
operating systems		Linux via third-party kernel module

aufs (short for advanced multi-layered unification filesystem) implements a union mount for Linux file systems. The name originally stood for AnotherUnionFS until version 2.

Developed by Junjiro Okajima in 2006,[1] aufs is a complete rewrite of the earlier UnionFS. 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]

  1. ^ "History of aufs". Retrieved 2015-11-08.
  2. ^ Goals and new features of aufs in the project's homepage
  3. ^ Aurora, Valerie (2009-04-07). "Unioning file systems: Implementations, part 2". LWN.net. Retrieved 2015-11-08.
  4. ^ "overlay filesystem · torvalds/linux@e9be9d5". GitHub. Retrieved 12 July 2016.
  5. ^ Hellwig, Christoph (2009-04-10). "Re: [RFC Aufs2 #5 28/29] export lookup functions". Retrieved 2015-11-08.
  6. ^ Okajima, Junjiro (2009-04-10). "Re: [RFC Aufs2 #5 28/29] export lookup functions". Retrieved 2018-10-01.