Dependability Evaluation of Cooperative Backup Strategies for Mobile Devices

Ludovic Courtès (1) , Ossama Hamouda (1) , Mohamed Kaâniche (1) , Marc-Olivier Killijian (1) , David Powell (1)

1 LAAS-TSF - Équipe Tolérance aux fautes et Sûreté de Fonctionnement informatique

Mobile devices (e.g., laptops, PDAs, cell phones) are increasingly relied on but are used in contexts that put them at risk of physical damage, loss or theft. This paper discusses the dependability evaluation of a cooperative backup service for mobile devices. Participating devices leverage encounters with other devices to temporarily replicate critical data. Permanent backups are created when the participating devices are able to access the fixed infrastructure. Several data replication and scattering strategies are presented, including the use of erasure codes. A methodology to model and evaluate them using Petri nets and Markov chains is described. We demonstrate that our cooperative backup service decreases the probability of data loss by a factor up to the ad hoc to Internet connectivity ratio.

Mots clés: cooperative backup; pervasive computing; dependability; data availability; modeling; assessment; delay tolerant networks

Domaines: Informatique mobile; Informatique ubiquitaire; Performance et fiabilité [cs.PF]

Ludovic Courtès, Ossama Hamouda, Mohamed Kaâniche, Marc-Olivier Killijian, David Powell. Dependability Evaluation of Cooperative Backup Strategies for Mobile Devices. 13th Pacific Rim International Symposium on Dependable Computing (PRDC 2007), Dec 2007, Melbourne, Australia. pp.139 - 146, ⟨10.1109/PRDC.2007.21⟩. ⟨hal-00851766⟩