F2Box: Cloudifying F2F Storage Systems with High Availability Correlation

Abstract

The increasing popularity of Cloud storage services is leading end-users to store their digital lives (including photos, videos, work documents, etc.) in the Cloud. However, many users are still reluctant to move their data to the Cloud due to the amount of control ceded to Cloud vendors. To let users retain the control over their data, Friend-to-Friend (F2F) storage systems have been presented in the literature as a promising alternative.However, as we show in this paper, pure F2F storage systems present a poor QoS, mainly due to availability correlations, which results in a loss of attractiveness by end users. To overcome this limitation, we propose a hybrid architecture that combines F2F storage systems and the availability of Cloud storage services to let users infer the right balance between user control and quality of service. This architecture, we called it F2BOX, is able to deliver such a balance thanks to the development of a new suite of data transfer scheduling strategies and a new redundancy calculation algorithm. The main feature of this algorithm is that allow users to adjust the amount of redundancy according to the availability patterns exhibited by friends. Our simulation and experimental results (in Amazon S3) demonstrate the high benefits experienced by end users as a result of the "cloudification" of F2F systems.

Cadros: The Cloud-Assisted Data Replication in Decentralized Online Social Networks

“…Only Eq. (11) in Case 1 should be rederived, because ‫ݐ‬ ௨௧ ௨ is known if the user is offline at time ‫,ݐ‬ i.e., ‫ݐ‬ ௨௧ ௨ is a constant. Therefore ‫ݓݐ‬ ௨_ ‫ݐ(‬ ᇱ ) should be calculated using Eq.…”

“…In 2012, Gracia-Tinedo et al [11] showed that pure F2F storage systems present a poor QoS, mainly due to the availability correlations, and proposed a hybrid architecture called F2Box to combine F2F storage systems and the cloud storage services. F2Box uses erasure coding to replicate the data and allow users to adjust the amount of redundancy according to the availability patterns exhibited by friends.…”

“…Further, the studies [11,31] show that the online/offline states of individual friends show high correlation, which indicates that many friends in a friend circle may go offline in the same time duration. When this happens, there may not be enough online friends to contribute the sufficient storage to save the data (and their replicas) published by the user.…”

“…In DOSNs, in order to protect the data privacy the centralized servers are bypassed and the data published by a user are stored and disseminated only among the friend circle of the user [4]. Although DOSNs can help protect the data privacy, maintaining Data Availability (DA) becomes a big challenge [11,29,32]. This is because if a friend of the user is offline, the data stored in the friend cannot be accessed by other friends.…”

Cloud-assisted dissemination in social overlays

“…The idea of using a cloud infrastructure to boost performance of P2P is not new. Cloud helpers are proposed in [17] to increase availability in a friendto-friend (F2F) backup system. This is similar to our work in that F2F systems are also based on social overlays, and that data is also confined to ego networks.…”