Um Modelo de Conjunto de Trabalho de Arquivos Aplicado à Recuperação de Backup P2P
Resumo
A alta intermitência e as limitações de banda passante dos nós características de sistemas de backup entre-pares (P2P, do inglês peer-to-peer) aumentam o tempo necessário para recuperar o backup, o que por sua vez aumenta a indisponibilidade do sistema (outage). Contudo, a qualquer instante, apenas uma fração dos dados é necessária para que o usuário prossiga com o seu trabalho. Se o sistema de backup for capaz de recuperar prioritariamente essa fração, o outage pode ser reduzido, mesmo que uma parcela significativa dos dados ainda esteja sendo recuperada. Neste artigo nós avaliamos o uso de um modelo de conjunto de trabalho de arquivos para aumentar a eficiência da recuperação de um sistema de backup P2P. Nós exploramos um modelo muito simples que prioriza os arquivos mais recentemente usados (LRU). A avaliação por simulação do mecanismo proposto mostra que ele é bastante eficiente, podendo atingir reduções de até 80% do tempo de outage, quando comparado ao mecanismo usado atualmente pelos sistemas de backup P2P.Referências
Landers, M. and Zang, H. and Tan, K. L. (2004) “PeerStore: Better Performance by Relaxing in Peer-to-Peer Backup”, In Proceedings of the 4th International Conference on Peer-to-Peer Computing, p. 72-79.
Lillibridge, M. and Elnikety, S. and Birrel, A. and Burrows, M. and Isard, M. (2003) “A cooperative internet backup scheme”, In Proceedings of the 2003 Usenix Annual Technical Conference, p. 29–41.
Batten, C. and Barr, K. and Saraf, A. and Treptin, S. (2001) “pStore: A secure peer-to-peer backup system”, Technical Memo MIT-LCS-TM-632, MIT Laboratory for Computer Science.
Oliveira, M. (2007) “OurBackup: Uma solução P2P de backup baseada em redes sociais”, Master of Science Thesis, Universidade Federal de Campina Grande, Campina Grande, PB.
Doucer, J. R. and Bolosky, W.J. (1999) “A Large-Scale Study of File-System Contents”, In Proceedings of the 1999 ACM SIGMETRICS Conference on Measurement and Modeling of Computer Systems, p. 59-69.
Tait. C. D. and Duchamp, D. (1991) “Detection and Exploitation of File Working Sets”, In Proceedings of the 11th International Conference on Distributed Computing Systems.
Kuenning, G. H. (1997) “Seer: Predictive File Hoarding for Disconnected Mobile Operation”, PhD thesis, University of California, Los Angeles, CA.
Santhosh, S. (2004) “Factoring file access patterns and user behavior into caching design for distributed file system”. Tech. Rep. MIST-TR-2004-013, Master of Science Thesis, Wayne State University.
Kuenning, G.H., Ma, W., Reiher, P.L. e Popek, G.J. (2002) “Simplifying Automated Hoarding 57 Methods”. In Proceedings. of the 5th ACM International Workshop on Modeling, Analysis and Simulation of Wireless and Mobile Systems (MSWiM'02), Atlanta, GA.
Saroiu, S., Gummadi, P.K. and Gribble, S. G. (2002) “A measurement study of peer-to-peer file sharing systems”. In Proceedings of the SPIE Multimedia Computing and Networking (MMCN2002)
Stutzbach, D. and Rejaie, R. (2006) “Understanding churn in peer-to-peer networks”. In Proceedings of the 6th ACM SIGCOMM on Internet measurement, pp. 189–202, New York, NY.
Crovella, M.E., Taqqu, M.S. and Bestavros, A. (1998) “Heavy-tailed probability distributions in the World Wide Web”. In Applications of Heavy-Tailed Probability Distributions, Adler, Feldman, and Taqqu Ed., Birkhauser, Boston, MA. pp. 3–25.
Horrigan, J. (2005) “Broadband Adoption at home in the United States: Growing but Slowing,” In Proceedings of the Telecommunications Policy Research Conference, also available at [link], accessed Oct. 2007.
Seer Public Traces. Web Page found at [link], Accessed in: October 2007.
Lillibridge, M. and Elnikety, S. and Birrel, A. and Burrows, M. and Isard, M. (2003) “A cooperative internet backup scheme”, In Proceedings of the 2003 Usenix Annual Technical Conference, p. 29–41.
Batten, C. and Barr, K. and Saraf, A. and Treptin, S. (2001) “pStore: A secure peer-to-peer backup system”, Technical Memo MIT-LCS-TM-632, MIT Laboratory for Computer Science.
Oliveira, M. (2007) “OurBackup: Uma solução P2P de backup baseada em redes sociais”, Master of Science Thesis, Universidade Federal de Campina Grande, Campina Grande, PB.
Doucer, J. R. and Bolosky, W.J. (1999) “A Large-Scale Study of File-System Contents”, In Proceedings of the 1999 ACM SIGMETRICS Conference on Measurement and Modeling of Computer Systems, p. 59-69.
Tait. C. D. and Duchamp, D. (1991) “Detection and Exploitation of File Working Sets”, In Proceedings of the 11th International Conference on Distributed Computing Systems.
Kuenning, G. H. (1997) “Seer: Predictive File Hoarding for Disconnected Mobile Operation”, PhD thesis, University of California, Los Angeles, CA.
Santhosh, S. (2004) “Factoring file access patterns and user behavior into caching design for distributed file system”. Tech. Rep. MIST-TR-2004-013, Master of Science Thesis, Wayne State University.
Kuenning, G.H., Ma, W., Reiher, P.L. e Popek, G.J. (2002) “Simplifying Automated Hoarding 57 Methods”. In Proceedings. of the 5th ACM International Workshop on Modeling, Analysis and Simulation of Wireless and Mobile Systems (MSWiM'02), Atlanta, GA.
Saroiu, S., Gummadi, P.K. and Gribble, S. G. (2002) “A measurement study of peer-to-peer file sharing systems”. In Proceedings of the SPIE Multimedia Computing and Networking (MMCN2002)
Stutzbach, D. and Rejaie, R. (2006) “Understanding churn in peer-to-peer networks”. In Proceedings of the 6th ACM SIGCOMM on Internet measurement, pp. 189–202, New York, NY.
Crovella, M.E., Taqqu, M.S. and Bestavros, A. (1998) “Heavy-tailed probability distributions in the World Wide Web”. In Applications of Heavy-Tailed Probability Distributions, Adler, Feldman, and Taqqu Ed., Birkhauser, Boston, MA. pp. 3–25.
Horrigan, J. (2005) “Broadband Adoption at home in the United States: Growing but Slowing,” In Proceedings of the Telecommunications Policy Research Conference, also available at [link], accessed Oct. 2007.
Seer Public Traces. Web Page found at [link], Accessed in: October 2007.
Publicado
12/07/2008
Como Citar
COLAÇO, Eduardo M.; OLIVEIRA, Marcelo Iury S.; SOARES, Alexandro S.; BRASILEIRO, Francisco; GUERRERO, Dalton S..
Um Modelo de Conjunto de Trabalho de Arquivos Aplicado à Recuperação de Backup P2P. In: WORKSHOP DE SISTEMAS OPERACIONAIS (WSO), 5. , 2008, Belém/PA.
Anais [...].
Porto Alegre: Sociedade Brasileira de Computação,
2008
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p. 135-146.
