Abstract: Cloud computing is one of the rising topic in the field of information technology. Now a day many organizations use this technology. There are many benefits of Cloud computing in terms of low cost and accessibility of Data. It is the smart technology and very popular, among all other computing paradigm. Security of cloud computing is a major factor in the cloud computing environment. Users store sensitive information with cloud storage providers but these providers may be untrusted. Due to risks of service availability failure and the possibility of malicious insiders in the single cloud Single Cloud is less popular. Security is one of the major factor that affect the growth as well as the development of cloud computing. This paper aims at the service availability of cloud. In this paper we give the solution for the cloud availability.

Keywords: Cloud computing, single cloud, multi-clouds, cloud storage, DepSky system, Shamir Secrete sharing algorithm, Data transfer security.