The number of disk drives available are 6 each having capacity of 200 GB. Also find out usable capacity of each RAID level.

Given : Number of hard disk/drives = 6

capacity of each disk drive = 200 GB

? To calculate storage efficiency for raid level 1,3,5 and 6

Also to calculate usable capacity of each raid level.

Solution :

Disk drive available = 6

Each drive of 200 GB

Therefore, total storage capacity = 6 x 200 = 1200 GB

RAID 3:

Storage efficiency (Raid 3) = $\frac{(n - 1)}{n} \times 100$

where n = number of disks

= $\frac{(6-1)}{6} \times 100$

= $\frac{5}{6} \times 100$

= 83.33 %

usable capacity of total capacity = $1200 \times \frac{83.33}{100}$

= 1200 x 0.83

= 996 GB

Raid 1:

Storage efficiency = 50% for Raid 1

Therefore, usable capacity of the total capacity = 1200 x 0.50 = 600 GB

Raid 5 :

Storage efficiency for Raid 5$ = (\frac{n-1}{n}) \times 100$

where n = number of disks

$= \frac{(6-1)}{6} \times 100$

$= \frac{5}{6} \times 100$

= 83.33 %

Usable capacity of the total capacity = 1200 x 9.83 = 996 GB

Raid 6 :

Storage efficiency for Raid 6 $= (\frac {n-2}{n}) \times 100$

where, n = number of disks

$= \frac{(6-2)}{6} \times 100$

$= \frac{4}{6} \times 100$ = 66.67 %

usable capacity of the total capacity $= 1200 \times \frac{66.67}{100}$

= 1200 x 0.67 = 804 GB