Moving change log tables to align to zones

Patent metadata

Field	Value
Publication number	US-11436153-B2
Application number	US-202016883901-A
Country	US
Kind code	B2
Filing date	May 26, 2020
Priority date	May 26, 2020
Publication date	Sep 6, 2022
Grant date	Sep 6, 2022

Abstract

The present disclosure generally relates to methods of operating storage devices. The storage device is comprised of a controller, a random access memory (RAM) unit, and a NVM unit, wherein the NVM unit is comprised of a plurality of zones. The RAM unit comprises a first logical to physical address table and the NVM unit comprises a second logical to physical address table. The zones are partitioned into sections, and each partitioned section aligns with a change log table. Data is written to each zone sequentially, and only one partitioned section is updated at a time for each zone. Each time a zone is erased or written to in the NVM unit, the first logical to physical address table is updated and the second logical to physical address table is periodically updated to match the first logical to physical address table.

First claim

What is claimed is:

1. A storage device, comprising:
a non-volatile storage unit, wherein a capacity of the non-volatile storage unit is divided into a plurality of zones, and wherein the non-volatile storage unit comprises a plurality of dies, each of the plurality of dies comprising a plurality of erase blocks;
a volatile memory unit, wherein the volatile memory unit stores a first logical to physical address table and a change log table, the first logical to physical address table associating logical block addresses of data to a physical address of where the data is stored in the non-volatile storage unit, wherein the change log table tracks changes made to the first logical to physical address table, the change log table having a smaller capacity than the first logical to physical address table; and
a controller coupled to the non-volatile storage unit and the volatile memory unit, wherein the controller is configured to:
write data to each zone of the plurality of zones sequentially;
partition the first logical to physical address table into sections, wherein each partitioned section aligns with the capacity of the change log table;
update a second logical to physical address table stored in the non-volatile storage unit, wherein the second logical to physical address table is updated in a partitioned section size of the first logical to physical address table; and
copy the change log table to the second logical to physical address table upon one or more of a predetermined amount of time expiring, the capacity of the change log table being filled, or a power loss event occurring.

2. The storage device of claim 1 , wherein the volatile memory unit is DRAM memory, and wherein the non-volatile storage unit is NAND memory.

3. The storage device of claim 1 , wherein the second logical to physical address table is updated every 20 seconds.

4. The storage device of claim 1 , wherein each zone is partitioned into an even number of sections.

5. The storage device of claim 1 , wherein the second logical to physical address table is updated each time a partitioned section of the second logical to physical address table is filled to capacity.

6. The storage device of claim 1 , further comprising one or more capacitors configured to provide power to the controller, wherein the controller is configured to use the power provided by the one or more capacitors to update the second logical to physical address table to match the first logical to physical address table in a power failure event.

7. The storage device of claim 1 , wherein one partitioned section of the second logical to physical address table is written to at a time.

8. The storage device of claim 1 , wherein each zone of the plurality of zones is erased in a zone capacity size.

9. The storage device of claim 8 , wherein the second logical to physical address table is updated each time a zone is erased.

10. A storage device, comprising:
a non-volatile storage unit, wherein a capacity of the non-volatile storage unit is divided into a plurality of zones, and wherein the non-volatile storage unit comprises a plurality of dies, each of the plurality of dies comprising a plurality of erase blocks;
a volatile memory unit configured to store a change log table and a first logical to physical address table, the change log table tracking changes made to the first logical to physical address table; and
a controller coupled to the non-volatile storage unit and the volatile memory unit, wherein the controller is configured to:
write data associated with one or more commands to a first zone of the plurality of zones sequentially, wherein each zone of the plurality of zones is partitioned into a plurality of sections, a partitioned section size aligning with a capacity of the change log table;
update the first logical to physical address table, the first logical to physical address table associating logical block addresses of the data associated with the one or more commands to a physical address of where the data associated with the one or more commands is stored in the first zone;
erase the data associated with the one or more commands from the first zone;
update the first logical to physical address table to show the first zone is empty;
update a second logical to physical address table stored in the non-volatile storage unit to match the first logical to physical address table, wherein the second logical to physical address table is updated in the partitioned section size of each zone; and
copy the change log table to the second logical to physical address table upon one or more of a predetermined amount of time expiring, the capacity of the change log table being filled, or a power loss event occurring.

11. The storage device of claim 10 , wherein the volatile memory unit is DRAM memory, and wherein each partitioned section of each zone begins with a zone starting logical block address.

12. The storage device of claim 10 , wherein the second logical to physical address table is updated 3 times per minute.

13. The storage device of claim 10 , wherein the first zone comprises a plurality of partitioned sections, and wherein one partitioned section of the first zone is updated each time data is written to the first zone.

14. The storage device of claim 10 , wherein the second logical to physical address table is updated during a power failure event.

15. The storage device of claim 10 , wherein each zone comprises 32 partitioned sections.

16. A storage device, comprising:
a non-volatile storage unit, wherein a capacity of the non-volatile storage unit is divided into a plurality of zones, and wherein the non-volatile storage unit comprises a plurality of dies, each of the plurality of dies comprising a plurality of erase blocks;
a volatile memory unit, the volatile memory unit storing a first logical to physical address table and a change log table, the first logical to physical address table associating logical block addresses of data to a physical address of where the data is stored in the non-volatile storage unit, wherein the change log table tracks changes made to the first logical to physical address table;
means for partitioning each zone of the plurality of zones into a plurality of sections, wherein each partitioned section of the plurality of sections aligns with a capacity of the change log table;
means for updating a partitioned section of a zone each time a command to write data to the zone is received;
means for updating the first logical to physical address table each time data is erased from the non-volatile storage unit, wherein the data is erased from the non-volatile storage unit in a zone capacity size;
means for updating a second logical to physical address table stored in the non-volatile storage unit to match the first logical to physical address table, wherein the second logical to physical address table is updated in a partitioned section size of each zone; and
means for copying the change log table to the second logical to physical address table upon one or more of a predetermined amount of time expiring, the capacity of the change log table being filled, or a power loss event occurring.

17. The storage device of claim 16 , further comprising means for updating the second logical to physical address table to match the first logical to physical address table in a power failure event.

18. The storage device of claim 16 , wherein the data is erased from the non-volatile storage unit in the size of a zone.

19. The storage device of claim 16 , wherein each

Assignees

• Western Digital Tech Inc

Inventors

• Helmick Daniel L
• Dancho Mark
• Jones Ryan R

Classifications

• G06F11/1048

  using arrangements adapted for a specific error detection or correction feature · CPC title

• G06F2212/7204

  Capacity control, e.g. partitioning, end-of-life degradation · CPC title

• G06F11/1441

  Resetting or repowering · CPC title

• G06F2212/7208

  Multiple device management, e.g. distributing data over multiple flash devices · CPC title

• G06F2212/1032

  Reliability improvement, data loss prevention, degraded operation etc · CPC title