``Assessing the Performance of Erasure Codes in the Wide-Area''

Rebecca L. Collins and James S. Plank.

Technical Report UT-CS-04-536, University of Tennessee, November, 2004.

This paper was published in DSN-2005: The International Conference on Dependable Systems and Networks. See http://web.eecs.utk.edu/~jplank/plank/papers/DSN-2005-CP.html for complete citation information and for the PDF of that paper.

Available via anonymous ftp to cs.utk.edu in CS-04-536.pdf.


The problem of efficiently retrieving a file that has been broken into blocks and distributed across the wide-area pervades applications that utilize Grid, peer-to-peer, and distributed file systems. While the use of erasure codes to improve the fault-tolerance and performance of wide-area file systems has been explored, there has been little work that assesses the performance and quantifies the impact of modifying various parameters. This paper performs such an assessment. We modify our previously defined framework for studying replication in the wide-area to include both Reed-Solomon and Low-Density Parity-Check (LDPC) erasure codes. We then use this framework to assess the performance of erasure coding in three wide-area, distributed settings. We conclude that as the set size, encoding rate, type of encoding and the distribution change, performance reflects a trade-off between downloading time and decoding time.

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