[54] SYSTEM AND METHOD FOR RECOVERING A SEGMENT DIRECTORY FOR A LOG STRUCTURED ARRAY
[75] Inventors: Juan Li; Dung K. Nguyen, both of San Jose; Mien Shih, Saratoga; Hai-Fang Yun, San Jose, all of Calif.
[73] Assignee: International Business Machines Corporation, Armonk, N.Y.
[21] Appl. No.: 09/079,868 [22] Filed: May 15, 1998
[51] Int. CI.7 G06F 11/00
[52] U.S. CI 714/6; 711/114
[58] Field of Search 714/6, 2, 7, 8,
714/13, 20, 25, 27, 32, 39, 41, 42, 44, 54, 5, 43, 48, 770, 771; 395/463, 441, 600; 711/111-114, 115, 133, 136; 710/61, 52
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Primary Examiner—Nadeem Iqbal
Attorney, Agent, or Firm—Esther E. Klein; Randall J. Bluestone
[57] ABSTRACT
In a storage system comprising an array of storage devices including a processor and memory, a plurality of data blocks are organized on the storage devices in segments striped across the storage devices. A main directory, stored in memory, contains the location on the storage device of each of the data blocks. For each segment a segment directory having information on the data blocks in the segment is stored on the storage devices. When a damaged segment directory is detected, a checkpoint of the main directory is written to the storage devices. A list is maintained of damaged segment directories such that segments on the damaged segment directories list are not garbage collected. Following a main directory recovery procedure, the damaged segment directories are reconstructed using the main directory.
19 Claims, 6 Drawing Sheets
