Storage device and deduplication method

A flash memory controller for use in a flash memory module in a storage device,

• wherein the flash memory module includes at least one flash memory chip for providing a storage area, wherein the storage area includes a physical unit memory area, and wherein the physical unit memory area includes a prescribed management information storage area, and
• wherein the storage device includes a storage controller for controlling the reading and writing of data from and into the flash memory module and for partitioning data in the flash memory module in a prescribed unit,
• wherein the flash memory controller
• performs deduplication processing to data of a data size that is equal or less than the prescribed unit, wherein the deduplication processing includes storing logical addresses of one or more corresponding logical unit memory areas in the prescribed management information storage area, wherein the one or more logical unit memory areas are associated with the physical unit memory area, and
• executes a reclamation process that includes
• managing a use degree as the total number of the logical addresses stored in the prescribed management information storage area and
• managing a duplication degree as the number of valid logical addresses corresponding to the physical unit memory area for the physical unit memory area, and
• returning the physical unit memory area to an unused status when a difference of the use degree and the duplication degree exceeds a default value in the physical unit memory area.

A method for use in a flash memory controller in a flash memory module,

• wherein the flash memory module includes at least one flash memory chip for providing a storage area, wherein the storage area includes a physical unit memory area, and wherein the physical unit memory area includes a prescribed management information storage area,
• wherein the method comprises:
• a first step of the flash memory controller performing deduplication processing by storing logical addresses of one or more corresponding logical unit memory areas in the prescribed management information storage area, wherein the one or more logical unit memory areas are associated with the physical unit memory area;
• and
• a second step of the flash memory controller executing a reclamation process that includes:
• managing a use degree as the total number of the logical addresses used stored in the prescribed management information storage area;
• managing a duplication degree as the number of valid logical addresses stored in the prescribed management information storage area;
• and
• returning the physical unit memory area to an unused status when a difference of the use degree and the duplication degree exceeds a prescribed value in the physical unit memory area.

A method for use in a flash memory controller in a flash memory module in a storage device,

• wherein the flash memory module includes at least one flash memory chip for providing a storage area, wherein the storage area includes a physical unit memory area, and wherein the physical unit memory area includes a prescribed management information storage area, and
• wherein the storage device includes a storage controller for controlling the reading and writing of data from and into the flash memory module and for partitioning data in the flash memory module in a prescribed unit, wherein the method comprises:
• the flash memory controller performing deduplication processing to data of a data size that is equal or less than the prescribed unit, wherein the deduplication processing includes storing logical addresses of one or more corresponding logical unit memory areas in the prescribed management information storage area, wherein the one or more logical unit memory areas are associated with the physical unit memory area;
• the flash memory controller performing a reclamation process that includes:
• managing a use degree as the total number of the logical addresses stored in the prescribed management information storage area;
• managing a duplication degree as the number of valid logical addresses corresponding to the physical unit memory area for the physical unit memory area;
• and
• returning the physical unit memory area to an unused status when a difference of the use degree and the duplication degree exceeds a default value in the physical unit memory area.