You are setting up some EBS volumes for a customer who has requested a setup which includes
a RAID (redundant array of inexpensive disks). AWS has some recommendations for RAID
setups. Which RAID setup is not recommended for Amazon EBS?
A.
RAID 1 only
B.
RAID 5 only
C.
RAID 5 and RAID 6
D.
RAID 0 only
Explanation:
With Amazon EBS, you can use any of the standard RAID configurations that you can use with a
traditional bare metal server, as long as that particular RAID configuration is supported by the
operating system for your instance. This is because all RAID is accomplished at the software
level. For greater I/O performance than you can achieve with a single volume, RAID 0 can stripe
multiple volumes together; for on-instance redundancy, RAID 1 can mirror two volumes together.
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.
http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/raid-config.html
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.