Storage control system with change logging mechanism and method of operation thereof

• US 8,909,851 B2
• Filed: 02/08/2012
• Issued: 12/09/2014
• Est. Priority Date: 02/08/2011
• Status: Active Grant

• Current Assignee: SanDisk Technologies LLC (Western Digital Corporation)
• Original Assignee: Smart Storage Systems Incorporated (Western Digital Corporation)
• Inventors: Jones, Ryan, Ellis, Robert W., Taylor, Joseph
• Primary Examiner(s): Bragdon, Reginald G.
• Assistant Examiner(s): Namazi, Mehdi
• Application Number:
  US13/369,195
• Publication Number:
  US 20120203958A1
• Time in Patent Office: 1,035 Days
• Field of Search: 711/103, 711/202, 711/205, 711/206, 711/207
• US Class Current: 711/103
• CPC Class Codes: G06F 12/0246 in block erasable memory, e.g. flash memory
• CPC Class Codes: G06F 2212/7201 Logical to physical mapping or translation of blocks or pages
• CPC Class Codes: G06F 2212/7207 management of metadata or control data
• CPC Class Codes: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management

Abstract

A method of operation of a storage control system including: providing a memory controller; accessing a volatile memory table by the memory controller; writing a non-volatile semiconductor memory for persisting changes in the volatile memory table; and restoring a logical-to-physical table in the volatile memory table, after a power cycle, by restoring a random access memory with a logical-to-physical partition from a most recently used list.

Claims

1. A storage control system comprising:

a memory controller;

a volatile memory storing, prior to a power cycle, a logical-to-physical translation table maintained by the memory controller, wherein the translation table includes a set of partitions ordered in accordance with most recent use of the partitions, each partition including physical address information for a plurality of logical addresses, wherein the memory controller updates respective partitions of the logical-to-physical translation table in volatile memory; and

a non-volatile semiconductor memory storing an update log written to by the memory controller, wherein the update log includes log records, each log record corresponding to an update by the memory controller to a respective partition of the logical-to-physical translation table in volatile memory;

wherein the volatile memory stores, after a power cycle, a restored portion of the logical-to-physical translation table stored in the volatile memory prior to the power cycle, wherein the restored portion of the logical-to-physical translation table is restored after the power cycle by traversing the log records in the update log in the non-volatile semiconductor memory in reverse chronological order to identify and restore a most recent version of each of a plurality of partitions of the logical-to-physical translation table.

2. The system of claim 1 wherein the memory controller includes a local buffer for pending memory operations.

8. The system of claim 1 wherein each log record in the update log contains updated translation information for a respective partition of the logical-to-physical partition table;

and

said traversing includes skipping a first log record in the update log when a more recent log record in the update log contains translation information for a same partition as the first log record.

9. The system of claim 1, wherein the logical-to-physical translation table in volatile memory comprises a doubly linked list of partitions ordered in accordance with most recent use.

10. The system of claim 1, wherein the non-volatile semiconductor memory comprises NAND flash memory.

3. A method of operation of a storage control system, performed by a memory controller in a storage system having volatile memory and non-volatile memory, the method comprising:

maintaining in volatile memory a logical-to-physical translation table, the translation table including a set of partitions ordered in accordance with most recent use of the partitions, each partition including physical address information for a plurality of logical addresses;

said maintaining including updating respective partitions of the logical-to-physical translation table in volatile memory;

writing to an update log in non-volatile semiconductor memory a log record for each updated partition of the logical-to-physical translation table in volatile memory;

after a power cycle, restoring to the volatile memory at least a portion of the logical-to-physical translation table stored in the volatile memory prior to the power cycle by traversing the log records in the update log in the non-volatile semiconductor memory in reverse chronological order to identify and restore a most recent version of each of a plurality of partitions of the logical-to-physical translation table.

4. The method of claim 3, wherein each log record in the update log contains updated translation information for a respective partition of the logical-to-physical partition table;

and

said traversing includes skipping a first log record in the update log when a more recent log record in the update log contains translation information for a same partition as the first log record.

5. The method of claim 3, wherein the logical-to-physical translation table in volatile memory comprises a doubly linked list of partitions ordered in accordance with most recent use.

6. The method of claim 3, wherein the non-volatile semiconductor memory comprises NAND flash memory.

7. The method of claim 3 wherein the memory controller includes a local buffer for pending memory operations.