Patent ID: 7774643

Claim:
A method of avoiding permanent data loss due to a defect in an information storage system, comprising: designating a first storage device to store data and not metadata, and a second storage device to store metadata; determining if the first storage device is a new storage device; if the first storage device is not a new storage device, determining a number of defective blocks in the first storage device and setting an index to the number of defective blocks in the first storage device; and if the first storage device is a new storage device, foregoing determining the number of defective blocks in the first storage device and setting the index to zero; detecting a defective block on the first storage device; incrementing the index upon detection of the defective block, wherein the index corresponds to a number of defective blocks identified on the first storage device, wherein the first storage device is identified as critical if the index reaches a predetermined value; in response to detecting the defective block, reconstructing data that was stored at the defective block to a different block on the first storage device, wherein reconstructing data comprises recreating the data originally stored in the defective block without using data from the defective block; and mapping the defective block to the different block with mapping metadata and storing the mapping metadata in the second storage device, wherein the mapping metadata identifies the defective block, the different block and the logical connection between the defective block and different block, wherein the data that was stored at the defective block is associated with a stripe of data comprising a number of blocks including at least one non-defective block and wherein the at least one non-defective block is not reconstructed.