An IT supporter is diagnosing a RAID 5 array with four hard drives. One of the disks has just failed. What can the technician do to get the array back?

If you use RAID 5 (disk striping with parity), a single drive failure usually indicates that your data will be fine as long as the failed drive is replaced. If you lose several drives at once, you'll have to restore from backup. The minimum number of disks for a RAID 5 array is three, however adding another disk to stripe across will boost speed.