Method and apparatus for operating an array of storage devices

Details Method and apparatus for operating an array of storage devices Method and apparatus for operating an array of storage devices

1992-05-06

1998-01-13

Envall, Jr., Roy N.

Excavating

395441, 39518204, G11C 2900

Patent

active

057086680

ABSTRACT:
A storage controller operates an array of parity protected data storage units as a RAID level 5. One of the storage units is a dedicated write assist unit. The assist unit is a temporary storage area for data to be written to the other units. When the array controller receives data from a host, it first writes the data to the assist unit. Because the assist unit is not parity protected and is only temporary storage, it is possible to write data to the assist unit sequentially, without first reading the data, greatly reducing response time. The array controller signals the CPU that the data has been written to storage as soon as it has been written to the assist unit. Parity in the array is updated asynchronously. In the event of system or storage unit failure, data can be recovered using the remaining storage units and/or the assist unit. The write assist unit also doubles as a spare unit. Data recovered from a failed unit can be stored on the write assist, which then ceases to function as a write assist unit and assumes the function of the failed storage unit.

REFERENCES:
patent: 4761785 (1988-08-01), Clark et al.
patent: 4817035 (1989-03-01), Timsit
patent: 4831581 (1989-05-01), Rubinfeld
patent: 4914656 (1990-04-01), Dunphy, Jr. et al.
patent: 5088081 (1992-02-01), Farr
patent: 5212784 (1993-05-01), Sparks
patent: 5257391 (1993-10-01), Dulac et al.
patent: 5258984 (1993-11-01), Menon et al.
patent: 5274499 (1993-12-01), Brant et al.
patent: 5283791 (1994-02-01), Halford
patent: 5313612 (1994-05-01), Satoh et al.
patent: 5341381 (1994-08-01), Fuller
patent: 5442752 (1995-08-01), Styczinski
IBM Technical Disclosure Bulletin, vol. 29, No. 11, Apr. 1987 "DASD Update Processing".
IBM Technical Disclosure Bulletin, vol. 29, No. 5, Oct. 1986 "Method for Scheduling Writes in a Duplexed DASD Subsystem".
Report No. UCB/CSD 88/467 Oct. 1988, Computer Science Division (EECS), University of California, Berkeley, California 94720--"Beating the I/O Bottleneck; A Case For Log-Structured File Systems" by John Ousterhout and Fred Douglis.
ACM Sigmod Conference, Chicago, Illinois, Jun. 1-3, 1988, "A Case For Redundant Arrays of Inexpensive Disks (RAID)" by David A. Patterson, Garth Gibson and Randy H. Katz (8 pages).

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