Title :
A measurement study of the Wuala on-line storage service
Author :
Mager, Thomas ; Biersack, Ernst ; Michiardi, Pietro
Author_Institution :
EURECOM, Sophia Antipolis, France
Abstract :
Wuala is a popular online backup and file sharing system that has been successfully operated for several years. Very little is known about the design and implementation of Wuala. We capture the network traffic exchanged between the machines participating in Wuala to reverse engineer the design and operation of Wuala. When Wuala was launched, it used a clever combination of centralized storage in data centers for long-term backup with peer-assisted file caching of frequently downloaded files. Large files are broken up into transmission blocks and additional transmission blocks are generated using a classical redundancy coding scheme. Multiple transmission blocks are sent in parallel to different machines and reliability is assured via a simple Automatic Repeat Request protocol on top of UDP. Recently, however, Wuala has adopted a pure client/server based architecture. Our findings and the underlying reasons are substantiated by an interview with a co-founder of Wuala. The main reasons are lower resource usage on the client side, which is important in the case of mobile terminals, a much simpler software architecture, and a drastic reduction in the cost of data transfers originating at the data center.
Keywords :
automatic repeat request; cache storage; client-server systems; peer-to-peer computing; software architecture; UDP; Wuala online storage service; automatic repeat request protocol; centralized storage; classical redundancy coding scheme; client-server based architecture; data centers; data transfer cost; file sharing system; frequently downloaded files; long-term backup; mobile terminals; network traffic; online backup; peer-assisted file caching; reverse engineer; software architecture; transmission blocks; Availability; Cryptography; Encoding; IP networks; Maintenance engineering; Peer to peer computing; Servers;
Conference_Titel :
Peer-to-Peer Computing (P2P), 2012 IEEE 12th International Conference on
Conference_Location :
Tarragona
Print_ISBN :
978-1-4673-2860-9
Electronic_ISBN :
978-1-4673-2861-6
DOI :
10.1109/P2P.2012.6335804