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%.

Abstract: Disclosed is a method of improving storage reliability comprising receiving an indicator of an impending failure of a first storage device in a RAID group. In response to the indicator, writing data to the first storage device is ceased. A first block of data directed to be written on the first storage device is written to a memory device. Data stored on the first storage device is copied to a second storage device. The first block of data is copied from the memory device to the second storage device. The RAID group is operated with the second storage device functioning in place of the first storage device. Data is read from said second storage device.

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%.

Abstract: Disclosed is a method of improving storage reliability comprising receiving an indicator of an impending failure of a first storage device in a RAID group. In response to the indicator, writing data to the first storage device is ceased. A first block of data directed to be written on the first storage device is written to a memory device. Data stored on the first storage device is copied to a second storage device. The first block of data is copied from the memory device to the second storage device. The RAID group is operated with the second storage device functioning in place of the first storage device. Data is read from said second storage device.