In the past decades

the amount of information data is growing in an unexpected speed and how to store and protect these large amounts of data becomes a problem.Cloud storage and data deduplication technology are the principal technology to solve the above problem.Deduplication technology is widely used in cloud storage systems.However

there are some shortcomings such as the expansion of the index information and the uncertainty of the data block in the current mainstream cloud storage technology

which lead to the waste of space and a big difference in the length of the data block.To overcome these shortcomings

through the study of cloud storage and data deduplication

this paper presents an optimal hierarchical deduplication strategy based on content defined chunking and proposes the corresponding algorithm

and achieves the purpose of saving memory space and obtaining better compression performance.Finally

this paper selects the content of the CNN news as a test set.By comparing the compression ratio and the compression time

the optimal hierarchical deduplication strategy has increased compression ratio by 3% and reduced compression time by 2% compared with the current mainstream deduplication strategy.