Benefits of EBS vs. instance-store (and vice-versa)

Question

I'm unclear as to what benefits I get from EBS vs. instance-store for my instances on Amazon EC2. If anything, it seems that EBS is way more useful (stop, start, persist + better speed) at relatively little difference in cost...? Also, is there any metric as to whether more people are using EBS now that it's available, considering it is still relatively new?

Answer 1

Instances with mounted EBS volumes are like virtual systems connected with virtual hard disks. In most of the cases, having this hard disk for your system is more preferable than just your system's internal memory, that is, in AWS terminology, the instance store.

Pros of EBS backed instances

• EBS volumes are instance independent so if the instances get terminated, your data won't be lost. 

• You can stop and start your EBS backed instances without losing any data on your EBS volume.

• You can dynamically modify the size the EBS volume

• You can mount an EBS volume that was in use before to a brand new instance and can access the data present in it.

Pros of Instances with instance store as the root volume

• Using EBS AMI can get costlier than some of the non-EBS backed AMI, so Instance store volumes are cost effective.

• Instance store volumes are local so they are faster and don't need any network-based storage.

• Instance store volumes are perfect for performance-critical data.