| 摘要 |
A system and method for providing a static snapshot, or image, of data stored on a mass storage system are disclosed. First, a preservation memory is cleared and a virtual device is created. Whenever a write is to be performed on the mass storage system, a check is made of the preservation memory to determine if it contains a block associated with the mass storage write address. If there is not, a copy of the block in the mass storage system at the block write address is placed in the preservation memory. Whenever a read is to be performed on the virtual device, a check is made of the preservation memory to determine if it contains a block associated with the virtual device read address. If there is such a block, that block is returned as the result of the virtual device read. Otherwise, the block at the virtual device block read address is returned as the result. |
