What is the minimum number of disks needed for a RAID array with parity and striping?

For a RAID array that incorporates both parity and striping, a minimum of three disks is required. This is because striping involves spreading data across multiple disks to improve performance, while parity provides a method for data recovery in the event of a disk failure by storing checksums or redundancy information.

In a RAID configuration that uses parity (such as RAID 5), one disk's worth of space is used to store the parity information for the data held on the other disks. Therefore, to effectively implement both data striping and parity, at least three disks are necessary: one disk to hold data, one for additional data, and one for the parity information that allows for recovery of lost data if one of the drives fails.

Having fewer than three disks would either not allow for proper data striping or not provide sufficient space for parity, ultimately compromising the redundancy and performance benefits that RAID is intended to offer. Thus, the minimum number of disks required for an effective RAID setup with both parity and striping is three.