What is the minimum number of disks required for RAID1?

What is the minimum number of disks required for RAID1?

• 2
• 1
• 4 or 5
• 3 

 

EXPLANATION

RAID 1 (mirroring) – the basic idea of such a solution is the replication (mirroring) of two or more discs. It means that while using RAID 1, an exact copy (or mirror) is created on two or more discs. Such a solution gives good read performance and reliability, but storage capacity must be compartmentalized. The reason for this is that the total storage must be equal to the capacity of the smallest disk. i.e.: in the case of an array composed of 3 discs – 250GM, 500GB and 1TB – the usable space will be equal to 250GB.