A small file merging and prefetching strategy based on access task in cloud storage

Aiming to improve the small file problem of a general distributed file system in cloud storage, a file merging and prefetching strategy based on a users' access task is proposed that improves the PLSA model. Analyzing the relationships among the access tasks, applications, and access files the strategy merge small files on the basis of tasks and selects prefetching files based the transition probability of the tasks. Efficiency model analysis and experimental results of a digital city prototype system based on HDFS all show that the proposed strategy has a high prefetching hit ratio and can effectively reduce the metadata servers' load and the response delay for users' request.