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Out of the stripping options available for the EBS volumes, which one has the following disadvantage: ‘Doubles
the amount of I/O required from the instance to EBS compared to RAID 0, because you’re mirroring all writes to
a pair of volumes, limiting how much you can stripe.’?

A.
Raid 0

B.
RAID 1+0 (RAID 10)

C.
Raid 1

D.
Raid

Explanation:
http://docs.aws.amazon.com/AWSEC2/latest/WindowsGuide/raid-config.html raid 0 and 1 are the common
types. Raid 5 and 6 are not recommended because of the extended stripe. If you encounter this question on the
exam I suspect the answer options will be different.
Raid 1 Disadvantage
Does not provide a write performance improvement; requires more Amazon EC2 to Amazon EBS bandwidth
than non- RAID configurations because the data is written to multiple volumes simultaneously.
Raid 0 Disadvantage
Performance of the stripe is limited to the worst performing volume in the set. Loss of a single volume results in
a complete data loss for the array.
Raid 5 and 6 notes
RAID 5 and RAID 6 are not recommended for Amazon EBS because the parity write operations of these RAID
modes consume some of the IOPS available to your volumes. Depending on the configuration of your RAID
array, these RAID modes provide 20-30% fewer usable IOPS than a RAID 0 configuration. Increased cost is a
factor with these RAID modes as well; when using identical volume sizes and speeds, a 2-volume RAID 0 array
can outperform a 4-volume RAID 6 array that costs twice as much.

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