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which one has the following disadvantage:

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.’ ?

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A.
Raid 0

B.
RAID 1+0 (RAID 10)

C.
Raid 1

D.
Raid

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14 Comments on “which one has the following disadvantage:

    1. Amr Eid says:

      Out of the striping 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 5
      B. Raid 6
      C. Raid 1
      D. Raid 2

      Answer: C




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  1. Chef says:

    This question is horrible. If you go to 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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  2. swagata mondal says:

    RAIS 1-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.




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  3. kay says:

    C, Raid -1

    The resulting size of a RAID 0 array is the sum of the sizes of the volumes within it, and the bandwidth is the sum of the available bandwidth of the volumes within it. The resulting size and bandwidth of a RAID 1 array is equal to the size and bandwidth of the volumes in the array. For example, two 500 GiB Amazon EBS volumes with 4,000 provisioned IOPS each will create a 1000 GiB RAID 0 array with an available bandwidth of 8,000 IOPS and 640 MB/s of throughput or a 500 GiB RAID 1 array with an available bandwidth of 4,000 IOPS and 320 MB/s of throughput.




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  4. Magwif says:

    I think Donkeynuts is correct
    the question is asking about mirroring all writes to a pair of volumes, limiting how much you can stripe

    you only mirror and stripe with answer B:




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  5. John says:

    Answer: C
    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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  6. blahblah says:

    B is correct

    A – Cannot be A b/c it says compared to RAID 0, this is RAID 0
    C – Cannot be C b/c question asks *Out of the striping options*, RAID 1 is not striped, see https://en.wikipedia.org/wiki/Standard_RAID_levels or excerpt below

    RAID 1 consists of an exact copy (or mirror) of a set of data on two or more disks; a classic RAID 1 mirrored pair contains two disks. This configuration offers no parity, striping, or spanning of disk space across multiple disks, since the data is mirrored on all disks belonging to the array, and the array can only be as big as the smallest member disk.

    Not sure what D is here, but if it’s RAID 5/6 not ‘RAID’ then those are not recommended on AWS and they also would not double IO b/c they use parity disks with their striped disks.




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