A mapped RAID group is generated that contains multiple RAID extents, and each one of the RAID extents is configured and arranged to indicate multiple drive extents that are each a contiguous region of non-volatile data storage in a physical drive. The RAID extents are divided into equal size subsets based on a requested RAID width. Drive extents are allocated from a drive extent pool such that the drive extents indicated by RAID extents contained in the same subset are all allocated from different ones of the physical drives. Logical block rotation is performed between the storage object and the mapped RAID group, causing host data written to consecutive blocks of the storage object address space to be directed to different ones of the RAID extents in the mapped RAID group. Data mirroring is performed between drive extents contained within each of the individual RAID extents of the RAID group.

A memory device is disclosed that includes a row of storage locations to store a data word, and a spare row element. The data word is encoded via an error code for generating error information for correcting X bit errors or detecting Y bit errors, where Y is greater than X. The spare row element has substitute storage locations. The logic is responsive to detected errors to (1) enable correction of a data word based on the error information where there are no more than X bit errors, and (2) substitute the spare row element for a portion of the row where there are at least Y bit errors in the data word.

A method for a controller of a hard disk including a plurality of platters, each platter including a data storage surface, the method including: obtaining data blocks, each block having to be or being stored on the hard disk, the number of blocks being less than that of surfaces of platters; calculating a redundancy data block based on each block, the number of redundancy data blocks added to the number of blocks being less than or equal to that of surfaces of platters; writing the redundancy data block on a platter surface, separate from the surfaces for storing each block; accessing data blocks corresponding to a data item to read from the hard disk and accessing a redundancy data block corresponding to the data item to read, each block accessed and each redundancy data block associated with the data item to read being accessed on a separate platter surface; and checking the integrity of the data item.

A method includes a processing module receiving data to store and determining error coding dispersal storage function parameters based on an error profile of one or more hard drives. The method continues with the processing module encoding at least a portion of the data in accordance with the error coding dispersal storage function parameters to produce a set of data slices. The method continues with the processing module defining addressable storage sectors within the one or more hard drives based on a number of data slices within the set of data slices to produce a set of addressable storage sectors. The method continues with the processing module storing data slices of the set of data slices in corresponding addressable storage sectors of the set of addressable storage sectors.

The present disclosure relates to techniques for providing data redundancy after reducing memory writes. In one example implementation according to aspects of the present disclosure, a storage system receives a storage command for providing data redundancy in accordance with a first data redundancy scheme. The storage system then implements a subsequent data redundancy in accordance with a second data redundancy scheme.

The present disclosure relates to techniques for providing data redundancy after reducing memory writes. In one example implementation according to aspects of the present disclosure, a storage system receives a storage command for providing data redundancy in accordance with a first data redundancy scheme. The storage system then implements a subsequent data redundancy in accordance with a second data redundancy scheme.