Patent
1995-03-03
1996-11-12
Swann, Tod R.
39518203, 39518204, 395404, G06F 1110, G06F 1200, G06F 1300
Patent
active
055748821
ABSTRACT:
A system and method are provided that is used by software implemented Redundancy Array of Inexpensive Disk (RAID) arrays to achieve adequate performance and reliability, as well as to improve performance or low cost hardware Raids. The enhancements to the basic RAID implementation speeds up recovery time for software RAIDS. A method is provided for storing data in an array of storage devices. A plurality of block locations on the storage devices are logically arranged as a parity group wherein a parity block stored in a block location as part of a parity group is logically derived from the combination of data blocks stored in the parity group, and each block in a parity group is stored on a different storage device. A plurality of parity groups are grouped into a parity group set. A request is received to write a new data block location on a storage device. The old data block stored at the block location is read. The new data block is written to the block location. When the parity set is in an unmodified state prior to the current write, an indicator is written to the storage device that the parity group set is in a modified state. In a preferred embodiment, this enhancement uses a bit map stored on disk, called Parity Group Set, (PGS) bit map, to mark inconsistent parity groups, replacing the Non-Volatile Random Access Memory, (NVRAM) used for similar purposes by hardware RAIDs. Further enhancements optimized sequential input/output, (I/O) data stream.
REFERENCES:
patent: 4761785 (1988-08-01), Clark et al.
patent: 4849929 (1989-07-01), Timsit
patent: 5088081 (1992-02-01), Farr
patent: 5109505 (1992-04-01), Kihara
patent: 5233618 (1993-08-01), Glider et al.
patent: 5249279 (1993-09-01), Schmenk et al.
patent: 5263145 (1993-11-01), Brady et al.
patent: 5287473 (1994-02-01), Mohan et al.
patent: 5301297 (1994-04-01), Menon et al.
patent: 5301310 (1994-04-01), Isman et al.
patent: 5333305 (1994-07-01), Neufeld
patent: 5341381 (1994-08-01), Fuller
patent: 5375128 (1994-12-01), Menon et al.
patent: 5390327 (1995-02-01), Labbers et al.
patent: 5398253 (1995-03-01), Gordon
patent: 5402428 (1995-05-01), Kakata et al.
patent: 5416915 (1995-05-01), Maltson et al.
patent: 5418921 (1995-05-01), Cortney et al.
patent: 5418925 (1995-05-01), DeMoss et al.
F. D. Lawlor "Efficient Mass Storage Parity Recovery Mechanism", IBM Technical Disclosure Bulletin vol. 24 No. 2 (Jul. 1981), pp. 986-987.
C. Crews et al. "Method for Background Parity Update in a Redundant Array of Inexpensive Disks (RAID)", IBM Technical Technical Disclosure Bulletin vol. 35 No. 5 (Oct. 1992), pp. 139-141.
Chen et al., "RAID: High-Performance, Reliable Secondary Storage" ACM Computing Surveys, vol. 26 No. 2, (Jun. 1994).
Patterson, Gibson and Katz, "A Case for Redundant Arrays of Inexpensive Disks (RAID)", Proceedings of the ACM SIGMOD Conference, 1988, pp. 109-116.
Menon and Cortney "The Architecture of a Fault-Tolerant Cached RAID Controller", 20th Annual Int'l Symposium on Computer Architecture, May 1993, pp. 76-86.
Stodolsky, Gibson and Holland, "Parity Logging Overcoming the Small Write Problem in Redundant Disk Arrays", 20th Int'l Symposium on Computer Architecture, May 1993, pp. 64-75.
Katz and Lee, "The Performance of Parity Placements in Disk Arrays", IEEE Transactions on Computers, vol. 42, No. 6, Jun. 1993.
Menon et al., "Floating Parity and Data Disk Arays", Journal of Parallel and Distributed Computing 17, 1993, pp. 129=14 139.
Menon, "Performance of RAID5 Disk Arrays with Read and Write Caching", Distributed and Parallel database, vol. 2, No. 3, pp. 261-294.
Menon Jaishankar M.
Riegel Geoffrey A.
Wyllie James C.
International Business Machines - Corporation
Klein Esther E.
Swann Tod R.
Thai Tuan V.
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