I am preparing for AWS certification and I found following question in mock test. The Question is as mentioned in below image :
And they have mentioned EBS volume in the question, I selected to choose "Provisioned IOPS SSD Volume" to implement scalable and high throughput.
But the correct answer was EFS with the following justification.
But, I think EBS volume can only be mapped with one EC2 instance at a time. Can we map one EBS volume with feet of multiple EC2 instance ?
No, you can't map an EBS volume to more than one instance at a time.
But EFS doesn't use EBS, and an EFS filesystem had no meaningful limit on the number of EC2 instances that can access it simultaneously.
The question isn't a very good one. In fact, it proposes an initial scenario that you would never use.
EBS volumes attached to members of an auto-scaling group would never be used to store CMS documents uploaded by users, because those volumes will ether be destroyed or left attached to nothing when the cluster scales in and some of the instances are terminated due to the decreased load.
The giveaway to the correct answer lies in the fact that the question asks for a scalable, high-throughput, POSIX-compliant filesystem and this is pretty much the definition of Amazon EFS. EFS will scale larger than the largest provisioned IOPS EBS volume.
