External Array Physical Drive Used Reallocated Sectors. This shows the number of sectors of the reallocation area that have been used by the physical drive. To see how many sectors were originally available for use in the reallocation area, refer to the factory reallocation information if it exists. Not all drives support factory reallocation. Because of the nature of magnetic disks, certain sectors on a drive may have media defects. The reallocation area is part of the disk drive that the drive manufacturer sets aside to compensate for these defects. The drive array controller writes information addressed from these unusable sectors to available sectors in the reallocation area. If too many sectors have been reallocated, there may be a problem with the drive. If the value cannot be determined, 4,294,967,295 is returned.