RAID Capacity Calculator

RAID1E Capacity Calculation:
Total usable storage capacity (TB):	0.75
RAID type:	RAID 1E (mirroring with striping)
Number of RAID groups:	1
Number of drives per RAID group:	3
Total number of drives:	3
Drive capacity (GB):	500
Capacity of a single RAID group (GB):	750
Space efficiency:	0.5 (50%)
Fault tolerance:	1 disk drive per RAID group
IO penalty (read):	1/1 (one RAID IO per each host IO)
IO penalty (write):	2/1 (2 RAID IOs per each host IO)
Minimum number of drives per RAID 1E group:	3
Single drive cost:
Cost per TB usable:
Total cost:

For comparison:
RAID 1 is traditionally implemented with two drives. Each data block is written to both drives in the set.
RAID 1E or RAID 1 Enhanced utilizes 3 or more drives by striping data blocks across all of the drives in the set. In addition, data blocks are mirrored to another stripe within the set. Blocks in this stripe are rearranged to ensure that copies of each data block are stored on different drives in the set. RAID 1E supports odd and even numbers of drives per raid group.
RAID 10 (1+0) is a combination of RAID 1 with RAID 0 - data blocks are striped across multiple identical RAID 1 groups. RAID 10 requires minimum of 4 drives, and the number of drives must be even.
RAID 0+1 is a combination of RAID 0 with RAID 1 - data blocks are mirrored across two identical RAID 0 groups. From a capacity point of view, RAID 10 (1+0) and RAID 0+1 comprised of the same number of disks are identical.
3-Way Mirror (Triple Mirror) is implemented with three drives. Each data block is written to all drives in the set.

Note: 1 TB = 1000 GB and 1 TiB = 1024 GiB

About:

This calculator computes RAID capacity characteristics for the most commonly used RAID types.

Provide the following parameters: the RAID type, the disk capacity in GB, the number of disks drives per RAID group and the number of RAID groups (if your storage system consists of more than one RAID group of the same configuration).
To perform calculation click Submit.

Optionally, enter the single disk cost to calculate the total storage cost and the cost per TB of usable capacity.

Supported RAID levels are:

RAID 0 (block-level striping without parity or mirroring);
RAID 1 (mirroring without parity or striping);
RAID 1E (mirroring with striping);
3-Way Mirror or Triple Mirror (mirroring without parity or striping);
RAID 3 (byte-level striping with a dedicated parity disk);
RAID 4 (block-level striping with a dedicated parity disk);
RAID 5 (block-level striping with distributed parity);
RAID 5E (RAID 5 Enhanced) and RAID 5EE (RAID 5E Enhanced) (block-level striping with distributed parity and integrated active distributed hot-spare);
RAID 6 (block-level striping with double distributed parity);
RAID 10 (1+0) (striped mirrors - a combination of multiple RAID 1 groups with RAID 0);
RAID 50 (combination of multiple RAID 5 groups with RAID 0);
RAID 60 (combination of multiple RAID 6 groups with RAID 0);
RAID-DP (stripe set with double parity and two dedicated parity disks);
RAID-TEC (triple erasure encoding);
RAID-Z1 (single parity with variable stripe width);
RAID-Z2 (double parity with variable stripe width);
RAID-Z3 (triple parity with variable stripe width).