Which type of RAID configuration requires minimum six drives?

Which type of RAID configuration requires minimum six drives?

• RAID 50 (RAID 5 + 0)
• RAID 100 (RAID 10+0)
• RAID 6
• RAID 60 (RAID 6 + 0) 

 

EXPLANATION

RAID 50, also called RAID 5+0, combines the straight block-level striping of RAID 0 with the distributed parity of RAID 5.[3] As a RAID 0 array striped across RAID 5 elements, minimal RAID 50 configuration requires six drives.

SOURCE

https://en.wikipedia.org/wiki/Nested_RAID_levels