Patent ID: 8289641
Filing Date: 2012-10-16
Classification: G11B

Abstract:
1. A method reducing the risk of data becoming unrecoverable in a data storage system including a plurality of data storage devices, each data storage device having a plurality of physical blocks to which data is written to in write operations and from which data is read in read operations, each data storage device having a plurality of block groups each associated with a subset of the plurality of physical blocks, the method comprising: recognizing read errors occurring in response to read operations; associating one of the block groups with each read error; counting the number of read errors associated with each block group; determining any one block group to be faulty when the counted number of read errors for that any one block group exceeds a predetermined threshold value, the data storage device having the block group determined to be faulty constituting a partially failed data storage device; and upon determining any one block group of any one of the plurality of data storage devices to be faulty: