A disk is segmented into a first data segment and a secondary data
segment. The secondary data segment stores a logical mirror of the first
data segment of another disk. Fast access to data stored on the disk is
provided by partitioning the disk such that the first data segment
includes the fast tracks of the disk and the secondary data segment
includes the slow tracks of the disk and forwarding all data requests to
the first data segment. Upon detecting a failure, the logical mirror of
data stored in the first data segment of the failed disk is accessible
from the secondary data segment of a non-failed disk. The first data
segment can be rebuilt quickly on another disk from the logical mirror
stored in the secondary data segment.