##### RAID Capacity Calculator
RAID type:
Drive capacity (GB):
Single drive cost:
Number of drives per RAID group:
Number of RAID groups:

 Results: Calculate performance... Total usable storage capacity (TB): 1.00 RAID type: RAID 1 (mirror) Number of RAID groups: 2 Number of drives per RAID group: 2 Total number of drives: 4 Drive capacity (GB): 500 Capacity of a single RAID group (GB): 500 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) Number of drives per RAID 1 group: 2 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.

This RAID calculator computes storage system characteristics based on the provided RAID level, number of disk drives, and drive 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).