Storage device, storage system, and control method

Patent metadata

Field	Value
Publication number	US-12293106-B2
Application number	US-202117447088-A
Country	US
Kind code	B2
Filing date	Sep 8, 2021
Priority date	Mar 17, 2021
Publication date	May 6, 2025
Grant date	May 6, 2025

Abstract

According to one embodiment, a storage device comprises a nonvolatile memory, and a controller configured to perform a first data write operation in a first mode, and to perform a second data write operation in a second mode. Data of a first number of bits is written per memory cell in the first mode. Data of a second number of bits is written per memory cell in the second mode. The second number is larger than the first number. The controller reserves one or more free blocks as write destination block candidates of the first data write operation, perform the first data write operation for one of the write destination block candidates, and perform a garbage collection.

First claim

What is claimed is:

1. A storage device comprising:
a nonvolatile memory including a plurality of blocks that are divided into a user capacity and an overprovisioning capacity; and
a controller configured to perform a first data write operation in a first mode for a block of a first block group, and to perform a second data write operation in a second mode for a block of a second block group, wherein
data of a first number of bits is written per memory cell in the first mode,
data of a second number of bits is written per memory cell in the second mode,
the second number is larger than the first number, and
the controller is configured to
reserve one or more free blocks in the plurality of blocks as write destination block candidates of the first data write operation, the reserved one or more free blocks being assigned from among the user capacity and the overprovisioning capacity, and a part of the first block group being a dedicated block as a static buffer and being provided in the overprovisioning capacity,
perform the first data write operation for one of the write destination block candidates, and
perform a garbage collection operation based on first control information received from an external device for an active block or blocks of the first block group and the second block group.

2. The storage device of claim 1 , wherein the first control information is configured to indicate whether the garbage collection operation is performed or not.

3. The storage device of claim 1 , wherein the first control information is configured to indicate how the garbage collection operation is performed or that the garbage collection operation is not performed.

4. The storage device of claim 1 wherein the first control information is configured to indicate whether the garbage collection operation is performed or not in an active idle period.

5. The storage device of claim 1 , wherein the first control information is configured to indicate that the garbage collection operation is performed in a standby entry period until the active block no longer exists, the garbage collection operation is performed in the standby entry period until a total size of free blocks becomes a certain size or more, or the garbage collection operation is not performed in the standby entry period.

6. The storage device of claim 1 , wherein the first control information is configured to indicate that the garbage collection operation is performed in a low power mode entry period until the active block no longer exists, the garbage collection operation is performed in the low power mode entry period until a total size of free blocks becomes a certain size or more, the garbage collection operation is performed in the low power mode entry period for a first period of time after a low power mode transition response, the garbage collection operation is performed in the low power mode entry period with maintaining a power consumption less than a first power after the low power mode transition response, or the garbage collection operation is not performed in the low power mode entry period.

7. The storage device of claim 1 , wherein the first control information is configured to indicate that the garbage collection operation is performed in a low power mode period for every second period of time, the garbage collection operation is performed in the low power mode period with maintaining a power consumption less than a second power, or the garbage collection operation is not performed in the low power mode period.

8. The storage device of claim 1 , wherein the first control information is configured to indicate that the garbage collection operation is performed with maintaining a write performance at a first percent or more in the first data write operation, or the garbage collection operation is not performed in the first data write operation.

9. The storage device of claim 8 , wherein a default write performance or a write performance if no garbage collection operation is performed is set to 100 percent.

10. The storage device of claim 1 , wherein the first control information is configured to indicate that the garbage collection operation is performed with maintaining a write performance less at a second percent of more in the second data write operation, or the garbage collection operation is not performed in the second data write operation.

11. The storage device of claim 10 , wherein a default write performance or a write performance if no garbage collection operation is performed is set to 100 percent.

12. The storage device of claim 1 , wherein the controller is configured to reserve, based on second control information received from the external device, one or more free blocks in the plurality of blocks as the write destination block candidates of the first data write operation.

13. The storage device of claim 12 , wherein the second control information is configured to indicate that the one or more free blocks are reserved as the write destination block candidates with maintaining a total size of the write destination block candidates at a first size.

14. The storage device of claim 12 , wherein the second control information is configured to indicate that the one or more free blocks are reserved as the write destination block candidates with maintaining a sum of a total size of the write destination block candidates of the first data write operation and a total size of the active block or blocks at a second size.

15. The storage device of claim 1 , wherein
the controller comprises a first controller, a second controller, and a third controller,
the first controller is configured to reserve the one or more free blocks,
the second controller is configured to perform the first data write operation and the second data write operation, and
the third controller is configured to perform the garbage collection operation.

16. The storage device of claim 15 , wherein
the first controller is configured to receive the first control information and transmit the first control information to the third controller.

17. The storage device of claim 15 , wherein
the second controller is configured to perform the second write operation when the third controller performs the garbage collection operation.

18. The storage device of claim 15 , wherein
the first controller is configured to provide an interface for setting the first control information to the external device.

19. The storage device of claim 15 , wherein
the third controller is configured to perform the garbage collection operation by designating a plurality of blocks in the second block group in which invalid and valid data are stored as garbage collection source blocks.

20. The storage device of claim 1 , wherein
each of the plurality of blocks is assigned to the block of the first block group or the block of the second block group.

21. A storage system comprising:
a storage device; and
a host connected to the storage device, wherein
the storage device comprises:
a nonvolatile memory including a plurality of blocks that are divided into a user capacity and an overprovisioning capacity; and
a controller configured to perform a first data write operation in a first mode for a block of a first block group, and to perform a second data write operation in a second mode for a block of a second block group, wherein
data of a first number of bits is written per memory cell in the first mode,
data of a second number of bits is written per memory cell in the second mode

Assignees

• Kioxia Corp

Inventors

• Amaki Takehiko
• Igahara Shunichi
• Hida Toshikatsu
• Kojima Yoshihisa

Classifications

• G06F3/064

  Management of blocks · CPC title

• G06F3/0659

  Command handling arrangements, e.g. command buffers, queues, command scheduling · CPC title

• G06F3/0679 Primary

  Non-volatile semiconductor memory device, e.g. flash memory, one time programmable memory [OTP] · CPC title

• G06F3/0625

  Power saving in storage systems · CPC title

• G06F2212/1044

  Space efficiency improvement · CPC title