What is the minimum number of disks required in a RAID5 array?

A single disk provides no redundancy or striping and cannot form any RAID array.

RAID 5 distributes parity information across all disks in the array. With 3 disks, two disks provide data striping and the third contributes parity, allowing the array to survive a single disk failure. Fewer than 3 disks cannot support both data striping and distributed parity simultaneously.

4 disks exceeds the minimum; while valid for RAID 5, it is not the minimum requirement.

5 disks also exceeds the minimum; RAID 5 requires only 3 disks at minimum.

2 disks are insufficient for RAID 5 because there is no room to distribute parity separately from data stripes.