Method and system for caching data in a storage system

• US 6,658,542 B2
• Filed: 11/13/2002
• Issued: 12/02/2003
• Est. Priority Date: 03/03/1999
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Benhase, Michael Thomas, Todd, Kenneth Wayne, Beardsley, Brent Cameron, Morton, Robert Louis
• Primary Examiner(s): BATAILLE, PIERRE MICHE
• Application Number:
  US10/293,508
• Publication Number:
  US 20030070041A1
• Time in Patent Office: 384 Days
• Field of Search: 711/4, 711/112, 711/113, 711/114, 711/162, 711/154, 711/144, 711/170, 711/118, 714/6, 714/7, 714/13, 714/15, 714/16, 707/202, 707/204, 707/205, 710/56
• US Class Current: 711/162
• CPC Class Codes: G06F 11/004 Error avoidance G06F11/07 and subgroups take precedence
• CPC Class Codes: G06F 11/0724 in a multiprocessor or a multi-core unit multiprocessors per se G06F15/80
• CPC Class Codes: G06F 11/0727 in a storage system, e.g. in a DASD or network based storage system drivers for digital recording or reproducing units G06F3/06; circuits for error detection or correction within digital recording or reproducing units G11B20/18; for distributed storage of data in networks, e.g. transport arrangements for network file system [NFS], storage area networks [SAN] or network attached storage [NAS], H04L67/1097
• CPC Class Codes: G06F 11/073 in a memory management context, e.g. virtual memory or cache management memory management G06F12/00; testing of static memory units G11C29/00
• CPC Class Codes: G06F 11/0793 Remedial or corrective actions recovery from an exception in an instruction pipeline G06F9/3861; by retry G06F11/1402; for recovering from a failure of a protocol instance or entity H04L69/40
• CPC Class Codes: G06F 12/0804 with main memory updating G06F12/0806 takes precedence
• CPC Class Codes: G06F 12/0866 for peripheral storage systems, e.g. disk cache
• CPC Class Codes: G06F 2212/312 In storage controller

Abstract

Disclosed is a system and method for caching data. A processor receives data from a host to modify a track in a first storage device. The processor stores a copy of the modified data in a cache and indicates in a second storage device the tracks for which there is modified data in cache. During data recovery operations, the processor processes the second storage device and data therein to determine the tracks for which there was modified data in cache. The processor then marks the determined tracks as failed to prevent data at the determined tracks in the first storage device from being returned in response to a read request until the failure is resolved. In further embodiments, in response to detecting a partial failure within the storage system, the processor would scan the cache to determine tracks for which there is modified data stored in the cache. The processor then stores in the second storage device information indicating the tracks having modified data in cache and schedules the destaging of the modified data from the cache to the first storage device. The processor is further capable of receiving and processing read/write requests directed to the first storage device before all the modified data is destaged from cache.

Claims