source: trunk/docs/proposed/README.lossmodel

Last change on this file was 4723af6, checked in by Brian Warner <warner@…>, at 2017-06-06T10:20:49Z

LAFS now stands for "Least-Authority File Store" rather than "Least-Authority File System". refs #2345

Signed-off-by: Daira Hopwood <daira@…>

  • Property mode set to 100644
File size: 1.1 KB
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1The lossmodel.lyx file is the source document for an in-progress paper
2that analyzes the probability of losing files stored in a Tahoe-LAFS
3file store under various scenarios.  It describes:
4
51.  How to estimate peer reliabilities, based on peer MTBF failure
6data.
7
82.  How to compute file loss probabilities, based on a given set of
9shares stored on peers with estimated reliabilities.  The peer
10reliabilities do not have to be uniform, and the model takes into
11account the file repair process.
12
133.  How to estimate Tahoe parameters for k (shares needed), n (shares
14distributed) and A (repair interval) to achieve a file reliability
15target.
16
174.  How to compute the estimated repair cost over time, discounted at
18a fixed rate, of maintaining a file for a time period T.
19
20Future work will also address the latter three issues in the context
21of "non-aggressive" repair, where repair will only be performed if
22too many shares are lost, and it will also extend the repair cost
23estimation model to suggest cost functions appropriate for common
24network architectures.
25
26A PDF of the current version of the file may be downloaded from:
27
28    http://willden.org/~shawn/lossmodel.pdf
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