Union mount: Difference between revisions

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A union mount is a mount that allows several filesystems to be mounted at one time, appearing to be one filesystem.

Rather than mounting each filesystem at a different place in the directory hierarchy, a union mount overlays the filesystems, creating a unified hierarchy. Thus, any given directory (or "folder") in the resulting filesystem may contain files and subdirectories from any or all of the underlying filesystems.

Generally one of the filesystems will be mounted read-write, while other filesystems are mounted read-only.

Union mounts are implemented by a union filesystem such as UnionFS and AUFS. They originated with Plan 9 and its concept of union directories.

Bibliography

Pendry, Jan-Simon (December 1995). "Union Mounts in 4.4BSD-Lite". Proceedings of the USENIX Technical Conference on UNIX and Advanced Computing Systems: 25–33. Retrieved 2007-11-25. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
Wright, Charles P. "Versatility and Unix Semantics in a Fan-Out Unification File System". Stony Brook University Technical Report FSL-04-01b. Retrieved 2007-11-25. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
Aurora, Valerie (March 2009). "Unioning file systems: Architecture, features, and design choices". lwn.net. Retrieved 2009-12-21. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
Aurora, Valerie (March 2009). "Union file systems: Implementations, part I". lwn.net. Retrieved 2009-12-21. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
Aurora, Valerie (April 2009). "Unioning file systems: Implementations, part 2". lwn.net. Retrieved 2009-12-21. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
Blunck, Jan (May 2009). "VFS based Union Mount (V3)". lwn.net. Retrieved 2009-12-21.

This computer-storage-related article is a stub. You can help Wikipedia by expanding it.

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-A '''union mount''' is a [[Mount (computing)|mount]] that allows several [[filesystem|filesystems]] to be mounted at one time, appearing to be one filesystem.
+A '''union mount''' is a [[Mount (computing)|mount]] that allows several [[filesystem]] to be mounted at one time, appearing to be one filesystem.
 Rather than mounting each filesystem at a different place in the directory hierarchy, a union mount overlays the filesystems, creating a unified hierarchy.  Thus, any given directory (or "folder") in the resulting filesystem may contain files and subdirectories from any or all of the underlying filesystems.
@@ Line 8: / Line 8: @@
 ==Bibliography==
-*{{cite journal|title=Union Mounts in 4.4BSD-Lite|journal=Proceedings of the USENIX Technical Conference on UNIX and Advanced Computing Systems|date=December 1995|first=Jan-Simon|last=[[Pendry]]|coauthors=[[Marshall Kirk McKusick]]|volume=|issue=|pages=25–33|id= |url=http://www.usenix.org/publications/library/proceedings/neworl/full_papers/mckusick.a|format=|accessdate=2007-11-25 }}
+*{{ journal|title=Union Mounts in 4.4BSD-Lite|journal=Proceedings of the USENIX Technical Conference on UNIX and Advanced Computing Systems|date=December 1995|first=Jan-Simon|last=[[Pendry]]|coauthors=[[Marshall Kirk McKusick]]|volume=|issue=|pages=25–33|id= |url=http://www.usenix.org/publications/library/proceedings/neworl/full_papers/mckusick.a|format=|accessdate=2007-11-25 }}
-*{{cite journal|title=Versatility and Unix Semantics in a Fan-Out Unification File System|journal=Stony Brook University Technical Report FSL-04-01b|date=|first=Charles P.|last=Wright|coauthors=Jay Dave, Puja Gupta, Harikesavan Krishnan, Erez Zadok, and Mohammad Nayyer Zubair|volume=|issue=|pages=|id= |url=http://www.filesystems.org/docs/unionfs-tr/index.html|format=|accessdate=2007-11-25 }}
+*{{ journal|title=Versatility and Unix Semantics in a Fan-Out Unification File System|journal=Stony Brook University Technical Report FSL-04-01b|date=|first=Charles P.|last=Wright|coauthors=Jay Dave, Puja Gupta, Harikesavan Krishnan, Erez Zadok, and Mohammad Nayyer Zubair|volume=|issue=|pages=|id= |url=http://www.filesystems.org/docs/unionfs-tr/index.html|accessdate=2007-11-25 }}
-*{{cite journal|title=Unioning file systems: Architecture, features, and design choices|journal=lwn.net|date=March 2009|first=Valerie|last=Aurora|coauthors=Henson|url=http://lwn.net/Articles/324291/|accessdate=2009-12-21}}
+*{{ journal|title=Unioning file systems: Architecture, features, and design choices|journal=lwn.net|date=March 2009|first=Valerie|last=Aurora|coauthors=Henson|url=http://lwn.net/Articles/324291/|accessdate=2009-12-21}}
-*{{cite journal|title=Union file systems: Implementations, part I|journal=lwn.net|date=March 2009|first=Valerie|last=Aurora|coauthors=Henson|url=http://lwn.net/Articles/325369/|accessdate=2009-12-21}}
+*{{ journal|title=Union file systems: Implementations, part I|journal=lwn.net|date=March 2009|first=Valerie|last=Aurora|coauthors=Henson|url=http://lwn.net/Articles/325369/|accessdate=2009-12-21}}
-*{{cite journal|title=Unioning file systems: Implementations, part 2|journal=lwn.net|date=April 2009|first=Valerie|last=Aurora|coauthors=Henson|url=http://lwn.net/Articles/327738/|accessdate=2009-12-21}}
+*{{ journal|title=Unioning file systems: Implementations, part 2|journal=lwn.net|date=April 2009|first=Valerie|last=Aurora|coauthors=Henson|url=http://lwn.net/Articles/327738/|accessdate=2009-12-21}}
-*{{cite journal|title=VFS based Union Mount (V3)|journal=lwn.net|date=May 2009|first=Jan|last=Blunck|url=http://lwn.net/Articles/333589/|accessdate=2009-12-21}}
+*{{ journal|title=VFS based Union Mount (V3)|journal=lwn.net|date=May 2009|first=Jan|last=Blunck|url=http://lwn.net/Articles/333589/|accessdate=2009-12-21}}
+{{Uncategorized stub|date=September 2010}}
-{{compu-storage-stub}}
+{{-storage-stub}}
 [[fr:Union mount]]