RAID Data Process

Each hard drive is used as a standalone disk. If a hard drive is damaged, all the data will be lost.

JBOD is a collection of hard drives that does not offer any RAID protection. The data are written to the physical disks sequentially. The total storage capacity is equal to the sum of the capacity of all member hard drives.

RAID 0 (striping disk) combines 2 or more hard drives into one larger volume. The data is written to the hard drive without any parity information and no redundancy is offered.

The total storage capacity of a RAID 0 disk volume is equal to the sum of the capacity of all member hard drives.

RAID 1 duplicates the data between two hard drives to provide disk mirroring. To create a RAID 1 array, a minimum of 2 hard drives are required.

The storage capacity of a RAID 1 disk volume is equal to the size of the smallest hard drive.

The data are striped across all the hard drives in a RAID 5 array. The parity information is distributed and stored across each hard drive. If a member hard drive fails, the array enters degraded mode. After installing a new hard drive to replace the failed one, the data can be rebuilt from other member drives that contain the parity information.

To create a RAID 5 disk volume, a minimum of 3 hard drives are required.

The storage capacity of a RAID 5 array is equal to (N-1) * (size of smallest hard drive). N is the number of hard drives in the array.

The data are striped across all the hard drives in a RAID 6 array. RAID 6 differs from RAID 5 that a second set of parity information is stored across the member drives in the array. It tolerates failure of two hard drives.

To create a RAID 6 disk volume, a minimum of 4 hard drives are required. The storage capacity of a RAID 6 array is equal to (N-2) * (size of smallest hard drive). N is the number of hard drives in the array.

RAID 10 combines four or more disks in a way that protects data against loss of non-adjacent disks. It provides security by mirroring all data on a secondary set of disks while using striping across each set of disks to speed up data transfers.

RAID 10 requires an even number of hard drives (minimum 4 hard drives). The storage capacity of RAID 10 disk volume is equal to (size of the smallest capacity disk in the array) * N/2. N is the number of hard drives in the volume.