In recent years, cloud storage systems have emerged as a promising technology for storing data blocks on various cloud servers. One of the main mechanisms in cloud storage systems is data replication, for which various solutions are proposed. Data replication's main target is achieving higher performance for data-intensive applications by addressing some critical challenges of this criterion, such as availability, reliability, security, bandwidth, and response time of data access. However, to the best of the author’s knowledge, there is no systematic, comprehensive, and complete survey in the cloud data replication despite its impacts and maturity. This paper presents a comprehensive survey and classification of state-of-the-art data replication schemes among different existing cloud computing solutions in the form of a classical classification to define current schemes on the topic and present open issues. The presented classification comprises three main classes; data deduplication schemes, data auditing schemes, and data handling schemes. A complete comparative comparison of the replication schemes highlights their main properties, such as utilized classes, type of the scheme, the place of implementation, evaluation tools, and their advantages and weaknesses. Finally, open issues and future uncovered or weakly covered research challenges are discussed, and the survey will be concluded.

近年来，云存储系统已成为一种有前途的技术，用于在各种云服务器上存储数据块。云存储系统中的主要机制之一是数据复制，为此提出了各种解决方案。数据复制的主要目标是通过解决该标准的一些关键挑战，例如可用性，可靠性，安全性，带宽和数据访问响应时间，来为数据密集型应用程序实现更高的性能。但是，据作者所知，尽管有影响和成熟度，但在云数据复制方面还没有系统，全面和完整的调查。本文以经典分类的形式对不同的现有云计算解决方案之间的最新数据复制方案进行了全面的调查和分类，以定义有关该主题的当前方案并提出未解决的问题。提出的分类包括三个主要类别：重复数据删除方案，数据审核方案和数据处理方案。对复制方案的完整比较比较突出了它们的主要属性，例如，使用的类，方案的类型，实现的位置，评估工具以及它们的优缺点。最后，讨论了未解决的问题和未来未发现或覆盖面较弱的研究挑战，并将得出调查结论。提出的分类包括三个主要类别：重复数据删除方案，数据审核方案和数据处理方案。对复制方案的完整比较比较突出了它们的主要属性，例如，使用的类，方案的类型，实现的位置，评估工具以及它们的优缺点。最后，讨论了未解决的问题和未来未发现或覆盖面较弱的研究挑战，并将得出调查结论。提出的分类包括三个主要类别：重复数据删除方案，数据审核方案和数据处理方案。对复制方案的完整比较比较突出了它们的主要属性，例如，使用的类，方案的类型，实现的位置，评估工具以及它们的优缺点。最后，讨论了未解决的问题和未来未发现或覆盖面较弱的研究挑战，并将得出调查结论。