Modeling Availability in Clouds for Mobile Computing

CIA - confidentiality, integrity, and availabilityof data are the three most desirable characteristicsof a data Cloud. Availability, in particular, is interesting when it comes to hosting data of enduserswho are always on the move (mobile clients).Conservatively, a full replication of data serviceswould be ideal. However, in a competitive market, where cost and quality of services play a majorrole in determining the existence of IT services, atotal replication-based solution will not yield the bestservice nor will it be economically viable to the endusers. Especially, for those users who are mobile andwould want their data available anywhere around theworld at any time, the optimization of data serviceavailability and cost of keeping it in the range 90%to 99.9% is challenging. This paper defines an availability metric and proposesan optimization model that makes use of multipleCloud data services for making data serviceshighly available at lower cost. By using user-definedavailability profiles, the revenue expected by a clouddata service provider is shaped accordingly. When theavailability metric, user-defined availability profile, the cost model, and the data service utilization areput together, mobile end-users get the best out oftheir data services and cost of making them availableanywhere anytime using the Cloud deployment model.