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UBC Theses and Dissertations
Elephant : the file system that never forgets Santry, Douglas J.
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 thesis 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 file-grain retention policies specified by users. 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. Most file systems have no built in support for recovering data.
Item Metadata
Title |
Elephant : the file system that never forgets
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Creator | |
Publisher |
University of British Columbia
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Date Issued |
1999
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Description |
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 thesis 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 file-grain retention policies specified by users. 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. Most
file systems have no built in support for recovering data.
|
Extent |
2879622 bytes
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Genre | |
Type | |
File Format |
application/pdf
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Language |
eng
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Date Available |
2009-06-26
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Provider |
Vancouver : University of British Columbia Library
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Rights |
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
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DOI |
10.14288/1.0051213
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URI | |
Degree | |
Program | |
Affiliation | |
Degree Grantor |
University of British Columbia
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Graduation Date |
1999-11
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Campus | |
Scholarly Level |
Graduate
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Aggregated Source Repository |
DSpace
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Item Media
Item Citations and Data
Rights
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.