An update model for network coding in cloud storage systems

Abstract

Abstract-The fast emerging cloud services have received a tremendous amount of attention in both industry and academia. Storage services such as Dropbox and iCloud enabled us to share files among multiple users or devices. Providing the benefits of network coding in distributed systems such as Peerto-Peer file sharing and multimedia streaming, researchers have also been trying to apply network coding in storage systems. Existing works have been focusing on mechanisms for preserving the level of redundancy when one or more nodes fail or leave the system. However, file updates, the most frequent operations performed on files, pose challenges in maintaining coded information in the system up to date. In other words, any change in the file will impact all coded blocks in the system, so all traces of the file must be completely replaced. This becomes costly since recomputing coded blocks is very CPU intensive and replacing all the coded blocks consumes an excessive amount of bandwidth. To the best of our knowledge, there has been no work addressing this update problem. To this end, we propose a Differential Update Model (DUM) that will update coded blocks by delivering only the changes in the file. We also present our objective view of the model through a complete analysis on computational complexity and bandwidth saving and simulated experiments.

Incremental updates based on graph theory for consumer electronic devices

“…The specific applications range from cloud storage [24], remote document synchronization [25], incremental backup [26] etc.…”

A subspace regenerating code with minimum decoding bandwidth

“…Thereafter, many researchers put great effort into designing practical efficient cloud storage schemes based on network coding. [6][7][8][9] focused on the updating problem of network coding storage system. By dealing with a group of equations with multiple variables so as to decrease the amount of variables, Wu and Dimakis [10] proposed a smart method based on interference alignment to reduce repair bandwidth.…”

A Network Coding Based Cloud Storage Scheme

“…Such a structure is beneficial to users on two facets: On the one hand, it decreases the complexity of encoding and decoding significantly. On the other hand, the file updating of Figure 3 Moreover, since the coding coefficients are invariant in our scheme, the method of [4] [5] can be utilized to decrease update bandwidth further.…”

“…Zakerinasab et al [4] [5] proposed a method to reduce update bandwidth for network coding based cloud. The key point is to keep the coding coefficients unchanged so that a new version code word turns out to be the sum of an old version word and a difference Δ between two versions.…”