aufs

On ( in version 1 Another Unionfs, version 2 and advanced multi layered unification filesystem ) is an overlay filesystem that writing data to non-writable storage media ( such as CD -ROMs and DVDs ) is required to (apparent). This requires at least two file systems are superimposed. In this case, a writable file system is not placed on the recordable. Now if a file is read, it is first tried to read them on the writable file system. If it is not there yet, it is read from the underlying non- writable file system. A write access is always on the writable file system.

On is a spinoff of unionfs, although it was not fully developed by Junjiro Okajima, who has delivered many bug fixes already for unionfs, new. Is used on eg Knoppix ( since version 5.1.0 ) and triggers unionfs for instability from.