US 2010/0169571 A1Published application

Data redundancy using two distributed mirror sets

AssigneeLSI Corporation

InventorsHariharan Kamalavannan, Suresh Dhanarajan, Senthil Kannan, Satish Subramanian, Selvaraj Rasappan

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Abstract

A method for storing data and two sets of distributed mirrored data disposed as data stripes which permits data recovery without the necessity of parity calculations, is described. Redundant data are stored in groups of five physical hard drives which are logically segmented into stripe groups, each stripe group having three data stripe sets wherein one data stripe is protected by two distributed mirror stripes in accordance with an algorithm. The present method provides protection for all one- and two-disk failures and certain three-disk drive failures, for each physical five disk group, and retains a usable disk capacity of 33%.

Claims11

Dependent claims

A method for storing data comprising:

dividing a first selected block of data to be stored into five data stripes, D1, D2, D3, D4, and D5;
generating first mirror data stripes M1, M2, M3, M4, and M5, wherein M1 is a mirror stripe of D1, M2 is a mirror stripe of D2, M3 is a mirror stripe of D3, M4 is a mirror stripe of D4, and M5 is a mirror stripe of D5;
generating second mirror data stripes M1′, M2′, M3′, M4′, and M5′, wherein M1′ is a mirror stripe of D1, M2′ is a mirror stripe of D2, M3′ is a mirror stripe of D3, M4′ is a mirror stripe of D4, and M5′ is a mirror stripe of D5;
providing a first set of five data storage units, S1, S2, S3, S4, and S5;
writing D1, M3 and M4′ onto S1;
writing D2, M4 and M5′ on S2;
writing D3, M5 and M1′ on S3;
writing D4, M1 and M2′ on S4;
and
writing D5, M2 and M3′ on S5.

7 more elements

Dependencies are inferred from the claim text.