关键词: 持续数据保护，部近时间点，差异算法，位表

Abstract: B1ock-level CDP system can't give clear recovery points with semantic information. Users have to execute data recovery several times to get correct data. Traditional algorithm for each data recovery will be time consuming and performance overhead costing. Target data of two neighboring point data recovery had little data gap. This paper divided neighboring point data recovery into four types, and presented a gap algorithm which eliminated more data and wrote lost data using bits table. It is proved by prototype experiment that the algorithm is correct and the less gap data, the more efficiency.

Key words: Continuous data protection, Neighboring point, Data gap algorithm, Bits table