# 00, what is the chargeback cost to the department for application storage?

A department within an organization requires 200 GB of storage for their business application. The production LUN is RAID 1+0 protected and has a local and remote replica. The local replica is on a RAID 1 LUN and the remote replica is on a five-disk RAID 5 LUN.

If the cost per GB of storage is \$2.00, what is the chargeback cost to the department for application storage?

A.
\$1050

B.
\$1500

C.
\$2100

D.
\$2900

## 10 Comments on “00, what is the chargeback cost to the department for application storage?”

1. Johnny says:

There are three LUNs. The production LUN is RAID 1+0, so 400 GB to get 200 GB.

The local replica is RAID 1. 400 GB to get 200 GB.

The remote replica is RAID 5. 250 GB to get 200 GB.

400 + 400 + 250 = 1050 GB. \$2/GB * 1050 GB = \$2,100

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2. Ric350 says:

How was the remote replica derived or calculated? 250GB to to 200GB? Can someone please explain this?

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1. Hzaru says:

Five-disk RAID 5 needs 1 disk for parity.

So:
X*(5-1) = 200
Where X is 50 -> total storage is 250 GB

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3. clayman88 says:

Although I understand the logic, I hate this question because it is not applicable to the real world. It is assuming that all disks are the same 200GB size. It also doesn’t take into account overhead i.e. if a disk is 200GB, you’re only getting ~180GB usable.

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1. kerkael says:

In facts, in real life, you would chargeback a service for the exact amount of storage it uses. Therefore, ou don’t count the Hard Disks, but you charge for the LUNs storage used. So this is valid in real life.

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