Implementing enhanced updates for indirection tables

• US 8,631,197 B2
• Filed: 08/11/2011
• Issued: 01/14/2014
• Est. Priority Date: 05/23/2011
• Status: Active Grant

• Current Assignee: JP Morgan Chase Bank, N.A. (JP Morgan Chase & Co)
• Original Assignee: HGST Netherlands B.V. (Western Digital Corporation)
• Inventors: Hall, David Robison
• Primary Examiner(s): PORTKA, GARY J
• Application Number:
  US13/207,935
• Publication Number:
  US 20120303884A1
• Time in Patent Office: 887 Days
• Field of Search: None
• US Class Current: 711/112
• CPC Class Codes: G11B 5/012 Recording on, or reproducing or erasing from, magnetic disks G11B17/00, G11B19/00 take precedence

Abstract

A method and a storage system are provided for implementing indirection tables and providing enhanced updates of the indirection tables for persistent media or disk drives, such as shingled perpendicular magnetic recording (SMR) indirection tables. A plurality of memory pools are used to store indirection data. An exception pointer table provides a pointer to an exception list for an I-Track. The exception list includes predetermined-size exception entries sorted by an offset from a start of the I-Track. An insert exception entry is provided for a new host write and merged to an updated exception list using an offset of the insert exception entry.

Claims

1. A method for implementing indirection tables and providing enhanced updates of the indirection tables for persistent media comprising:

using a plurality of memory pools to store indirection data;

providing an exception pointer table and providing a respective exception list pointer to each of a plurality of exception lists;

sorting predetermined-size exception entries of each said exception list by an offset from a start of an I-Track and storing each said exception list in one said memory pool; and

providing an insert exception entry for a new host write; and

merging the insert exception entry into an initial exception list to provide an updated exception list using an offset of the insert exception entry.

2. The method as recited in claim 1 wherein the persistent media includes a Shingled Disk Drive.

3. The method as recited in claim 1 wherein providing an exception pointer table for providing a respective pointer to each of a plurality of exception lists includes providing indirection tables memory allocation control logic coupled to a controller to control storing of the indirection data.

4. The method as recited in claim 1 wherein providing an insert exception entry for a new host write;

and merging the insert exception entry into an initial exception list to provide an updated exception list using an offset of the insert exception entry includes merging said updated exception list into a static random access memory (SRAM).

5. The method as recited in claim 4 includes freeing the memory pool for the initial exception list in dynamic random access memory (DRAM).

6. The method as recited in claim 4 includes writing the updated exception list into a new memory pool in dynamic random access memory (DRAM).

7. The method as recited in claim 5 includes providing an updated exception list pointer to the new memory pool.

8. The method as recited in claim 1 wherein sorting predetermined-size exception entries of each said exception list by an offset from a start of an I-Track and storing each said exception list in one said memory pool includes providing each predetermined-size exception entries with said offset, a length and a drive Logical Block Address (LBA).

9. The method as recited in claim 6 wherein sorting predetermined-size exception entries of each said exception list by an offset from a start of an I-Track and storing each said exception list in one said memory pool includes using a split and indirect pointers for providing multiple exception lists for one said I-Track.

10. The method as recited in claim 1 wherein merging the insert exception entry into an initial exception list to provide an updated exception list using an offset of the insert exception entry includes keeping said predetermined-size exception entries in order using said offset of each of said predetermined-size exception entries.

11. An apparatus for implementing indirection tables and providing enhanced updates of the indirection tables for persistent media comprising:

a plurality of memory pools to store indirection data;

an exception pointer table providing a respective exception list pointer to each of a plurality of exception lists;

each said exception list including predetermined-size exception entries being sorted by an offset from a start of an I-Track and each said exception list being stored in one said memory pool; and

an insert exception entry for a new host write being merged into an initial exception list to provide an updated exception list using an offset of the insert exception entry.

12. The apparatus as recited in claim 11 wherein the persistent media includes a Shingled Disk Drive.

13. The apparatus as recited in claim 11 includes a controller, and indirection tables memory allocation control logic coupled to said controller to control storing of the indirection data in said plurality of memory pools.

14. The apparatus as recited in claim 11 wherein said insert exception entry for a new host write being merged into an initial exception list to provide an updated exception list includes said updated exception list being stored in a static random access memory (SRAM).

15. The apparatus as recited in claim 14 includes said updated exception list being written into a new memory pool in dynamic random access memory (DRAM).

16. The apparatus as recited in claim 14 includes the memory pool for said initial exception list being freed in dynamic random access memory (DRAM).

17. The apparatus as recited in claim 11 includes a split and indirect pointers for providing multiple exception lists for one said I-Track.

18. A data storage system comprising:

a persistent media;

a controller, and indirection tables memory allocation control logic coupled to said controller for implementing indirection tables and providing enhanced updates of the indirection tables for persistent media;

said controller and said indirection tables memory allocation control logic using a plurality of memory pools for storing indirection data;

an exception pointer table providing a respective exception list pointer to each of a plurality of exception lists;

each said exception list including predetermined-size exception entries being sorted by an offset from a start of an I-Track and each said exception list being stored in one said memory pool; and

an insert exception entry for a new host write being merged into an initial exception list to provide an updated exception list using an offset of the insert exception entry.

19. The data storage system as recited in claim 18 includes said updated exception list being stored in a static random access memory (SRAM).

20. The data storage system as recited in claim 18 includes said updated exception list being written into a new memory pool in dynamic random access memory (DRAM).