StackSync

Abstract

The design of elastic file synchronization services like Dropbox is an open and complex issue yet not unveiled by the major commercial providers, as it includes challenges like fine-grained programmable elasticity and efficient change notification to millions of devices. In this paper, we propose a novel architecture for file synchronization which aims to solve the above two major challenges. At the heart of our proposal lies ObjectMQ, a lightweight framework for providing programmatic elasticity to distributed objects using messaging. The efficient use of indirect communication: i) enables programmatic elasticity based on queue message processing, ii) simplifies change notifications offering simple unicast and multicast primitives; and iii) provides transparent load balancing based on queues.Our reference implementation is StackSync, an open source elastic file synchronization Cloud service developed in the context of the FP7 project CloudSpaces. StackSync supports both predictive and reactive provisioning policies on top of ObjectMQ that adapt to real traces from the Ubuntu One service. The feasibility of our approach has been extensively validated with an open benchmark, including commercial synchronization services like Dropbox or OneDrive.

An Active File Mode Transition Mechanism Based on Directory Activation Ratio in File Synchronization Service

“…In this paper, we proposed an active file mode change mechanism that automatically changes the file mode to online or local mode by considering the local storage usage ratio and file access delay time according to the directory activation ratio in the file synchronization service for cloud storage. Most research works regarding file synchronization do not support file mode change functionality [1][2][3][4][5][6][7]. In the existing manual file mode change method [8][9][10], the file mode is not changed without the user's request.…”

“…Research has been performed aiming to improve file synchronization performance in cloud storage [2][3][4][5][6][7]. Andriani et al [2] proposed a cloud storage synchronization architecture called Cloud4NetOrg.…”

“…MataSync proposes the pPaxos algorithm, which is a client-based modification of the existing Paxos [31] algorithm, and proposes a data replication algorithm that reduces the cost of maintaining the consistency of replicated data in order to synchronize file modifications consistently among multiple cloud services. Lopez et al [6] proposed a StackSync architecture that provides elastic file synchronization based on a lightweight message queue framework called ObjectMQ. The elastic file synchronization is an efficient method of providing resources such as servers or message queue objects according to synchronization overhead, by increasing or decreasing resources.…”

“…Existing research on file synchronization [1][2][3][4][5][6][7] focuses on methods to improve synchronization performance to efficiently process large files for many users, but do not support online and local mode change functions for synchronized files. Some commercial cloud file synchronization services [8][9][10][11] provide the functionality to change the online and local modes of files, but this function only allows users to manually change the mode of selected files on an on-demand basis.…”