One embodiment of the present invention provides a system that facilitates validation
of data retrieved from a secondary storage device. The system operates by receiving
a write request to write new data to a block of the secondary storage device, and
calculating a new checksum value from the new data. The system also retrieves a
current checksum value and an old checksum value associated with the block of the
secondary storage device. Next, the system performs a checksum write operation
to a validation device to update the current checksum value and the old checksum
value, and then performs a data write operation to the secondary storage device
to write the new data to the block of the secondary storage device.
