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OverlayFS
From Gentoo Wiki (test)
Overlayfs (Overlay Filesystem) differs from other union filesystem implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases.[1]
The option to enable OverlayFS exists in Linux kernels 3.18 and higher.[2]
Installation
Kernel
KERNEL Enable OverlayFS (OVERLAY_FS) support
File systems ---> [*] Overlay filesystem support
Usage
Once enabled in the kernel OverlayFS can be controlled using the mount command.
See also
External resources
- http://lwn.net/Articles/447650/ - A LWN article written by Jonathan Corbet in June 2011 covering vises and virtues of OverlayFS.
- An informative AskUbuntu.com thread.
- Overlay fs in the Linux git repository.