You have an application running in us-west-2 that requires six EC2 instances running at all times. With three
AZs available in that region (us-west-2a, us-west-2b, and us-west-2c), which of the following deployments
provides 100 percent fault tolerance if any single AZ in us-west-2 becomes unavailable?
Choose 2 answers
A.
Us-west-2a with two EC2 instances, us-west-2b with two EC2 instances, and us-west-2c with two EC2
instances
B.
Us-west-2a with three EC2 instances, us-west-2b with three EC2 instances, and us-west-2c with no EC2
instances
C.
Us-west-2a with four EC2 instances, us-west-2b with two EC2 instances, and us-west-2c with two EC2
instances
D.
Us-west-2a with six EC2 instances, us-west-2b with six EC2 instances, and us-west-2c with no EC2
instances
E.
Us-west-2a with three EC2 instances, us-west-2b with three EC2 instances, and us-west-2c with three EC2
instances
D, E.
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0
DE
如有一个可用区不可用,其他可用区EC2综合达到6台.
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1
Can any one explain the reason for D & E
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0
option A : 2 2 2
option B : 3 3 –
option C : 4 2 2
option D : 6 6 –
option E : 3 3 3
so if one availability zone fails you need to have a backup of 6 instances running
only D & E has that chances
5
0
Here is the Cache point : Requires six EC2 instances running at all times.
so at any cost you need 6 instance. so D & E matches requirement.
0
0
D E
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0