RAID 0 / 1 / 0+1 / 5 / JBOD: Descriptions and explanations

RAID (Redundant Array of Inexpensive Disks), defines a technology that allows you to combine multiple hard drives to form a single storage unit. Also known as an array, the advantage of RAID is to offer a large and powerful storage capacity that is more fault tolerant.

But we will see that not all RAID installations offer the same advantages.


RAID 0
RAID 0, or striping, allows you to combine all hard drives together to form a virtual disk. The size is equal to the number of disks included in the RAID 0 array, multiplied by the smallest storage capacity on the drives. It is therefore preferable to use disks of the same size, so as to avoid any loss of storage capacity.

We will take the example of three hard drives which are each respectively 120, 160 and 250 gigabytes, to form a RAID 0 array. We will obtain a virtual drive of 3 x 120GB, for a total of 360GB. You have therefore lost 170GB.

RAID 0 offers better performance in read/write by cutting the data into segments (striping). It then simultaneously writes on all the disks that are included in the array. The performance depends on the size of the striping that you chose when you created the RAID 0 array.

A smaller size will have faster data access, with the disks functioning simultaneously. Conversely, a larger size will improve the load time. This is idea for a multitasking environment. But the size is quite difficult to evaluate, and strongly depends on the use that you plan for your PC, which means that it is optimal to choose an intermediary size, between 64 and 128 Kb.

Besides this performance increase, RAID 0 offers no fault tolerance in the event of hardware failure. If one of the drives dies, then you will lose all of your data. Unless you have of course created a backup of your hard drive by using one of our favourite programs, Acronis True Image 10 Home Edition.