A fine snapshot technology in volume level was presented which could be used to keep old data flexibly and frequently

to recovery from deletion

to limit exposure to data lose for logic volumes.First

two kinds of logic volumes namely

checkpoint and finesnap were designed and used as containers of snapshot data.Linking checkpoint volumes and finesnap volumes together by the order of time could make up of a hybrid snapshot chain

with which both good per-formance and high efficiency on storage usage were available.Second

a bitmap in each finesnap volume to accelerate data searching and reduce the memory exhausted was incorporated.Evaluation results from representative experiments demonstrate that the prototype system

named LV-Fine

has the ability to provide good performance

and to introduce less storage overhead than LVM2

the famous cluster virtualization system.