With the emergence of the storage in cloud, more and more people are moving their data to the cloud. With increased data in cloud, service providers of cloud face a challenge to ensure maximum data availability and reliability. Data replication is highly employed by commercial large scale cloud storage systems to improve data availability and reliability. In this paper, already existing replication techniques are studied and examined for various parameters like, availability, reliability, storage space consumption, storage cost, bandwidth consumptions, number of replicas, response time. A survey of the different replication strategies is accomplished consolidating the above mentioned parameters. The outcome of such survey will enable the users to determine the replication strategy best suited for their needs.

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Cloud Computing Data Availability Dynamic Replication Reliability