Distributed subsystem sparing

摘要

A method and apparatus for sharing distributed spares of a first array with a second array in a storage subsystem which included a number of storage arrays requires that at least a first array of the subsystem has available distributed spares, and that at least a second array has a same number of "rows" as the first array, for spare sharing. When a device failure occurs on the second array, the data and parity blocks of the failed device are reconstructed and placed in the spares of the first array, and the block addresses are appropriately remapped to the spares. Distributed spare sharing is possible because the first array is configured to include at least one spare region/row, and the second array will never lose a number of blocks greater than the common number of rows in the first array in a single device failure. Distributed spare sharing optimizes a storage subsystem, because all spares within arrays of the subsystem having an equal number of rows must be depleted before device replacement becomes mandatory.