Patent ID: 7313721

Claim:
A method for performing a preemptive reconstruct of a redundant array of disks while the redundant array is still fault-tolerant, the method comprising: determining that a number of errors by one of the disks in the redundant array has exceeded an error threshold; reading data from a second one of the disks in the redundant array and writing the data to a spare disk, in response to said determining, wherein the data of the second one of the disks in the redundant array is a mirrored copy of data of the one of the disks; replacing the one of the disks in the redundant array with the spare disk, after said reading and writing is complete; and while said reading and writing, writing second data to the one of the disks in the redundant array in response to a user write request including the second data, thereby maintaining the fault-tolerance of the redundant array.