PDL Abstract

File System Virtual Appliances: Portable File System Implementations

Carnegie Mellon University Parallel Data Lab Technical Report CMU-PDL-09-102, May 2009.

Michael Abd-El-Malek1, Matthew Wachs1, James Cipar1, Karan Sanghi1, Gregory R. Ganger1,
Garth A. Gibson1,2, Michael K. Reiter3

1Carnegie Mellon University
2Panasas, Inc.
3University of North Carolina at Chapel Hill

Electrical and Computer Engineering
Carnegie Mellon University
Pittsburgh, PA 15213


File system virtual appliances (FSVAs) address the portability headaches that plague file system (FS) developers. By packaging their FS implementation in a VM, separate from the VM that runs user applications, they can avoid the need to port the file system to each OS and OS version. A small FS-agnostic proxy, maintained by the core OS developers, connects the FSVA to whatever OS the user chooses. This paper describes an FSVA design that maintains FS semantics for unmodified FS implementations and provides desired OS and virtualization features, such as a unified buffer cache and VM migration. Evaluation of prototype FSVA implementations in Linux and NetBSD, using Xen as the VMM, demonstrates that the FSVA architecture is efficient, FS-agnostic, and able to insulate file system implementations from OS differences that would otherwise require explicit porting.

KEYWORDS: Portable file systems, third-party file system development, operating systems, virtual machines

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