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OverlayFS

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OverlayFS
Developer(s)Open Source Community
Full nameOverlay File System
Features
File system
permissions
POSIX
Other
Supported
operating systems
Linux, FreeBSD and NetBSD

OverlayFS is a filesystem service for Linux which implements a union mount for other file systems.

It was merged into the Linux kernel mainline in 2014, in kernel version 3.18.[1][2]

The main mechanics of OverlayFS relates to the merging of directory access when both filesystems present a directory for the same name. Otherwise, OverlayFS presents the object, if any, yielded by one or the other, with the "upper" filesystem taking precedence. Unlike some other overlay filesystems, the directory subtrees being merged by OverlayFS do not necessarily have to be from distinct filesystems.[3]

OverlayFS supports whiteouts and opaque directories in the upper filesystem to allow file and directory deletion.[3]

References

  1. ^ "OverlayFS commit to Linux".
  2. ^ "OverlayFS Proposed For The Linux 3.18 Kernel".
  3. ^ a b "OverlayFS documentation". kernel.org.