DCD-Based Block Device Snapshot System

This paper recommend a system SSDCD(snapshot system on DCD) implementing snapshot on the block device.By using and improving the technology of DCD(Disk Caching Disk),this system implements the function of snapshot on the block device with the method of COW(copy on write).This system lightens the affect of small writing after the snapshot is taken.Then it achieves better I/O performance.Without any impact on current file system and the structure of disk data,it gets the high performance of currency,