Deciding when to forget in the Elephant file system

Deciding when to forget in the Elephant file system (1999)

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by Douglas S. Santry , Michael J. Feeley , Norman C. Hutchinson , Alistair C. Veitch , Ross W. Carton , Jacob Ofir

Venue:	17TH ACM SYMPOSIUM ON OPERATING SYSTEMS PRINCIPLES (SOSP ’99), PUBLISHED AS OPERATING SYSTEMS REVIEW, 34(5):110–123, DEC. 1999
Citations:	160 - 5 self

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Datum	Value	Source
TITLE	Deciding when to forget in the Elephant file system	user correction
AUTHOR NAME	Douglas S. Santry	user correction
AUTHOR AFFIL	Department of Computer Science; University of British Columbia	user correction
AUTHOR NAME	Michael J. Feeley	user correction
AUTHOR AFFIL	Department of Computer Science; University of British Columbia	user correction
AUTHOR NAME	Norman C. Hutchinson	user correction
AUTHOR AFFIL	Department of Computer Science; University of British Columbia	user correction
AUTHOR NAME	Alistair C. Veitch	user correction
AUTHOR AFFIL	Department of Computer Science; University of British Columbia	user correction
AUTHOR NAME	Ross W. Carton	user correction
AUTHOR AFFIL	Department of Computer Science; University of British Columbia	user correction
AUTHOR NAME	Jacob Ofir	user correction
AUTHOR AFFIL	Department of Computer Science; University of British Columbia	user correction
ABSTRACT	Modern file systems associate the deletion of a file with the immediate release of storage, and file writes with the irrevocable change of file contents. We argue that this behavior is a relic of the past, when disk storage was a scarce resource. Today, large cheap disks make it possible for the file system to protect valuable data from accidental delete or overwrite. This paper describes the design, implementation, and performance of the Elephant file system, which automatically retains all important versions of user files. Users name previous file versions by combining a traditional pathname with a time when the desired version of a file or directory existed. Storage in Elephant is managed by the system using filegrain user-specified retention policies. This approach contrasts with checkpointing file systems such as Plan-9, AFS, and WAFL that periodically generate efficient checkpoints of entire file systems and thus restrict retention to be guided by a single policy for all files within that file system. Elephant is implemented as a new Virtual File System in the FreeBSD kernel.	user correction
YEAR	1999	user correction
VENUE	17TH ACM SYMPOSIUM ON OPERATING SYSTEMS PRINCIPLES (SOSP ’99), PUBLISHED AS OPERATING SYSTEMS REVIEW, 34(5):110–123, DEC. 1999	user correction
CITATIONS	24 found	ParsCit 1.0