Patent ID: 7093182

Claim:
A method for controlling a data storage apparatus including a plurality of n storage devices, the method comprising: selecting a control value m indicative of a degree of data redundancy, m being an integer variable from the group consisting of 1 to n−1 inclusive; logically configuring each storage device into one or more stripes, each stripe including H data portions for storing user data and Q data redundancy portions for storing redundancy data, H and Q being positive integers and H/Q<(n−m)/m; and providing a data redundancy function and a corresponding set of data recovery functions based on the value n and the control value m, the data redundancy function being useful for generating redundancy data from user data, the data redundancy function being such that the user data stored in any subset of m or fewer unavailable storage devices is recoverable from the user data and the redundancy data stored in n−m remaining storage devices using the data recovery functions.