SK0-004 · Question #49
Two RAID arrays are created from eight disks. One is created using RAID 6, the other is created using RAID 5 with a hot spare. Which of the following is the operational difference between these…
The correct answer is A. RAID 6 has the ability to recover from two disks simultaneously failing. RAID 6 uses dual distributed parity, enabling survival of two simultaneous disk failures, which is the key operational advantage over RAID 5 with a hot spare.
Question
Two RAID arrays are created from eight disks. One is created using RAID 6, the other is created using RAID 5 with a hot spare. Which of the following is the operational difference between these configurations?
Options
- ARAID 6 has the ability to recover from two disks simultaneously failing.
- BThe RAID 5 array will be significantly faster than the RAID 6 array.
- CThe RAID 6 array will be significantly faster than the RAID 5 array.
- DRAID 6 has a higher storage capacity than RAID 5.
How the community answered
(55 responses)- A51% (28)
- B7% (4)
- C27% (15)
- D15% (8)
Why each option
RAID 6 uses dual distributed parity, enabling survival of two simultaneous disk failures, which is the key operational advantage over RAID 5 with a hot spare.
RAID 6 writes two independent parity blocks across all disks, so the array remains fully operational even if any two disks fail at exactly the same time. RAID 5 with a hot spare can only tolerate one failure at a time - a second failure during the rebuild window causes total data loss. This makes RAID 6 operationally superior in environments where simultaneous or back-to-back failures are a concern.
RAID 5 is not significantly faster than RAID 6 - both use striping with parity, and any write speed difference is minor due to RAID 6 computing a second parity block, not a dramatic performance gap.
RAID 6 is not significantly faster than RAID 5 - in fact, RAID 6 has slightly higher write overhead due to the additional parity calculation, making this claim incorrect.
With 8 disks, RAID 6 uses 2 for parity leaving 6 usable, while RAID 5 with a hot spare uses 1 for parity and 1 as spare leaving 6 usable - the usable capacity is the same, not higher for RAID 6.
Concept tested: RAID 6 vs RAID 5 fault tolerance comparison
Source: https://learn.microsoft.com/en-us/windows-server/storage/storage-spaces/storage-spaces-fault-tolerance
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