Data storage device and operating method thereof for performing a garbage collection operation in consideration of a lifetime of a nonvolatile memory device
A data storage device includes a nonvolatile memory device; and a controller suitable for setting a termination condition of a garbage collection operation based on an over-provisioning ratio of the nonvolatile memory device, performing the garbage collection operation, and terminating the garbage collection operation according to the termination condition.
1. A data storage device comprising:
a nonvolatile memory device having a memory region which includes an over-provisioning region and a non-over-provisioning region;
an over-provisioning management unit configured to adjust, according to a request from an external device, an over-provisioning ratio of the nonvolatile memory device which is a ratio of the over-provisioning region to the memory region, by replacing a bad region in the non-over-provisioning region with a portion of the over-provisioning region thereby reducing the over-provisioning ratio; and
a garbage collection unit configured to sets a termination condition for a garbage collection operation that is performed on the non-over-provisioning region, so that the garbage collection operation is terminated when the termination condition is satisfied,
wherein the termination condition is based on a number of free memory blocks in the non-over-provisioning region on which the garbage collection operation is performed, and
wherein when the over-provisioning ratio is reduced, the garbage collection unit sets a lower number of free memory blocks in the non-over-provisioning region as the termination condition so that the garbage collection operation is terminated when the number of free memory blocks in the non-over-provisioning region resulting from the garbage collection operation exceeds the lower number of free memory blocks.
2. The data storage device according to claim 1 , wherein the over-provisioning unit and the garbage collection unit are included in a controller of the data storage device.
3. The data storage device according to claim 1 , wherein the garbage collection unit sets a higher number of free memory blocks as the termination condition when the over-provisioning ratio is increased.
4. The data storage device according to claim 1 , wherein the garbage collection unit adjusts the termination condition according to a variation of the over-provisioning ratio.
5. The data storage device according to claim 2 , wherein the controller generates the free memory blocks by copying valid data of a dirty memory block to another memory block, and erasing the dirty memory block.
6. A method for operating a data storage device including a nonvolatile memory device having a memory region which includes an over-provisioning region and a non-over-provisioning region, the method comprising:
adjusting, by an over-provisioning management unit according to a request from an external device, an over-provisioning ratio of the nonvolatile memory device which is a ratio of the over-provisioning region to the memory region, by replacing a bad region in the non-over-provisioning region with a portion of the over-provisioning region thereby reducing the over-provisioning ratio;
setting, by a garbage collection unit, a termination condition of a garbage collection operation that is performed on the non-over-provisioning region, the termination condition being based on a number of free memory blocks in the non-over-provisioning region on which the garbage collection operation is performed; and
performing the garbage collection operation,
wherein when the over-provisioning ratio is reduced, the garbage collection unit sets a lower number of free memory blocks in the non-over-provisioning region as the termination condition so that the garbage collection operation is terminated when the number of free memory blocks in the non-over-provisioning region resulting from the garbage collection operation exceeds the lower number of free memory blocks.
7. The method according to claim 6 , wherein the over-provisioning management unit and the termination unit are included in a controller of the data storage device.
8. The method according to claim 6 , wherein the setting of the termination condition includes setting a higher number of free memory blocks as the termination condition when the over-provisioning ratio is increased.
9. The method according to claim 6 , further comprising adjusting the termination condition according to a variation of the over-provisioning ratio.
10. The method according to claim 6 , wherein the free memory blocks are generated by copying valid data of a dirty memory block to another memory block, and erasing the dirty memory block.