A Stackable Unification File System

Unionfs logo    This project builds a stackable unification file system, which can appear to merge the contents of several directories (branches), while keeping their physical content separate. Unionfs is useful for unified source tree management, merged contents of split CD-ROM, merged separate software package directories, data grids, and more. Unionfs allows any mix of read-only and read-write branches, as well as insertion and deletion of branches anywhere in the fan-out. To maintain unix semantics, Unionfs handles elimination of duplicates, partial-error conditions, and more. Unionfs is part of the larger FiST project.

Software Download:

Unionfs releases and snapshots are available via FTP.

Kernel Version Compatibility:

Kernel Version Unionfs Version
2.4.x (x>19) 1.0.14
2.6.x (x<9) Not Supported
2.6.9 - 2.6.15 1.1.5
2.6.16 1.2
2.6.17 1.3
2.6.18-rc CVS Snapshots

Mailing Lists:

Click on the list name below to access the subscription Web page. That page will also tell you how to post to the list, access the lists' archives, change your subscription status, etc.

List Name Purpose Who Can Subscribe Who Can Post Comments
unionfs For users' and developers' questions, announcements, bug reports, and general. Anyone Subscribers only  
unionfs-cvs For CVS commit logs Anyone No one: automated CVS logs only  

Miscellaneous:

If you find a problem, please describe it in detail and submit a bug report via Bugzilla.

Some Unionfs users congregate in #unionfs on the FreeNode IRC network.

Various articles and tutorials involving Unionfs:

Projects Using Unionfs:

No.NameDescription
1ALT LinuxALT Linux distribution build kit, that allow you to preparing customized distribution or LiveCD, based on ALT Linux Sisyphus packages repository
2ArchieArch Live Project
3Ark Linux LiveArk Linux Live is a "Live CD" version of Ark Linux.
4BlutopiaCluster Life-cycle Management, IBM Research Austin
5ClusterixClusterix is a modular Linux live CD based on Morphix, Knoppix and Debian GNU/Linux.
6DanixCzech Knoppix-like distribution
7DSS-LiveA system development environment to create Debian-based live Linux systems.
8EliveA Debian-based LiveCD centered around the Enlightenment window manager.
9GeLuXSwiss French Linux distribution based on Morphix
10Generations LinuxBoot/LiveCD containing GNU/Linux and KDE
11GoblinXGoblinX is a live CD based on Slackware, with standardized themes for novice users.
12grmlLiveCD for system administrators and texttool-users
13INSERTA Linux rescue system with NTFS write support and virus scanning that fits on a credit-card size CD.
14KanotixKnoppix-based LiveCD.
15KnoppixBootable CD with a collection of GNU/Linux Software
16LiveBackupA Framework to create bootable live-ISO's from installed Linux systems
17m-distAudio/MIDI LiveCD based on Slackware.
18Mandriva OneLive & Install CD with everything for office work, Internet and multimedia.
19MiniMythA network-boot distribution that runs the MythTV PVR software.
20MorphixModular Knoppix-based LiveCD
21NOPPENLINUXSUSE Linux based LiveCD
22PaiPixA remastered Knoppix with a focus on Scientific applications.
23rBuilder OnlineAn online tool for creating and maintaining tailored Linux distributions including LiveCDs, Installable CDs, VMWare Images, QEMU Images, and other image types from custom package sets.
24redWall FirewallA bootable CD-ROM Firewall.
25Scientific Linux Live SystemLiveCD and LiveDVD of Scientific Linux
26SLAXSmall Slackware-based bootable CD containing the Linux OS.
27T2A "Distribution Build Kit" that allows you to select various targets for a customized distribution (e.g., router, desktop, or LiveCD).
28TaprobaneA Debian-based LiveCD that is customized for convenience without "dumbing down" the user's experience.
29TuguxPortuguese Linux Distribution
30XarnoppixA Catalan-localized LiveCD focused on education

Conference and Workshop Papers:

# Title (click for html version) Formats Published In Date Comments
1 UnionFS: User- and Community-oriented Development of a Unification Filesystem PS PDF BibTeX 2006 Ottawa Linux Symposium Jul 2006  

Journal Articles:

# Title (click for html version) Formats Published In Date Comments
1 On Incremental File System Development PS PDF BibTeX ACM Transactions on Storage (TOS) May 2006  
2 Versatility and Unix Semantics in Namespace Unification PS PDF BibTeX ACM Transactions on Storage (TOS) Feb 2006  
3 Unionfs: Bringing File Systems Together BibTeX Linux Journal Dec 2004  

Technical Reports:

# Title (click for html version) Formats Published In Date Comments
1 Versatility and Unix Semantics in a Fan-Out Unification File System PS PDF BibTeX Stony Brook U. CS TechReport FSL-04-01b Oct 2004  

Current Students:

# Name (click for home page) Program Member Since
1 David Quigley MS Sep 2005
2 Yiannis Pericleous BS/MS Sep 2006
3 Josef "Jeff" Sipek BS Jul 2005

Past Students:

# Name (click for home page) Program Period Current Location
1 Charles P. Wright PhD May 2003 - May 2006 Research Staff Member, Network Server Systems Software group, IBM T. J. Watson Research Center (Hawthorne, NY)
2 Jay Pradip Dave MS May 2003 - Dec 2003 Software Design Engineer in Test (SDET), Windows Security and Access Control team (WSAC), Windows Security group, Core Operating Systems Division (COSD), Microsoft (Seattle, WA)
3 Puja Gupta MS Jan 2003 - Dec 2003 File Systems Engineer, Apple (Cupertino, CA)
4 Arun Krishnakumar MS Jan 2005 - Dec 2005  
5 Harikesavan Pathangi Krishnan MS Jan 2003 - Dec 2003 Tacit Networks (South Plainfield, NJ)
6 Mohammad Nayyer Zubair MS Jan 2004 - Dec 2004 Software Engineer, Falconstor (Melville, NY)
7 David Quigley BS Dec 2004 - Aug 2005 SFS Scholar, Stony Brook U. CS M.S. program (Stony Brook, NY)
8 Mohammad Nayyer Zubair BS May 2003 - Dec 2003 Stony Brook U. CS M.S. program (Stony Brook, NY)

Sponsors:

# Sponsor Amount Period Type Title (click for award abstract)
1 NSF Trusted Computing (TC) $400,000 2003-2006 Sole PI A Layered Approach to Securing Network File Systems


(Last updated: Wed Sep 20 11:46:20 EDT 2006)