SG0-001 · Question #585
Given an array with sixteen 300GB drives, a storage administrator needs to know how much raw usable space can be made available while still maintaining a highly available RAID configuration with two…
The correct answer is C. 3.9TB, RAID 5. The question asks for the maximum usable capacity from 16x 300GB drives, with two hot spares, in a highly available RAID configuration. After allocating two drives for hot spares, 14 drives remain for the RAID array.
Question
Given an array with sixteen 300GB drives, a storage administrator needs to know how much raw usable space can be made available while still maintaining a highly available RAID configuration with two hot spares. Which of the following is the MAXIMUM capacity that can be allocated and at which RAID level?
Options
- A2.1TB, RAID 1
- B3.6TB, RAID 6
- C3.9TB, RAID 5
- D4.8TB, RAID 0
How the community answered
(45 responses)- A9% (4)
- B20% (9)
- C60% (27)
- D11% (5)
Why each option
The question asks for the maximum usable capacity from 16x 300GB drives, with two hot spares, in a highly available RAID configuration. After allocating two drives for hot spares, 14 drives remain for the RAID array.
RAID 1 mirroring with 14 drives would result in 7 mirrored pairs, yielding (14/2) * 300GB = 2.1TB usable space, which is less than RAID 5.
RAID 6 with 14 drives (N-2 parity) would yield (14-2) * 300GB = 12 * 300GB = 3.6TB usable space, which is less than RAID 5.
With 14 drives remaining for the RAID array (16 total - 2 hot spares), RAID 5 uses N-1 drives for data and one for parity. This configuration provides (14-1) * 300GB = 13 * 300GB = 3900GB, or 3.9TB, and is considered highly available.
RAID 0 provides no redundancy and is not considered highly available, failing a key requirement of the question, and even then, 14 drives in RAID 0 would yield 4.2TB, not 4.8TB.
Concept tested: RAID levels, capacity calculation, hot spares
Source: https://learn.microsoft.com/en-us/windows-server/storage/disk-management/understanding-raid
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