a method and system that allows the distribution of hot spare space across multiple disk drives that also store the data and redundant data in a fully active array of redundant independent disks , so that an automatic rebuilding of the array to an array of the identical level of redundancy can be achieved with fewer disk drives . the method configures the array with d disk drives of b physical blocks each . n user data and redundant data blocks are allocated to each disk drive , and f free blocks are allocated as hot spare space to each disk drive , where n + f & lt ;= b , and × f )& gt ;= n . thus , rebuilding of data and redundant blocks of a failed disk drive in the free blocks of the remaining disk drives is enabled after m disk drive failures .