Choose a volume
EBS
- can only be attached to one instance (except multi-attach io1/io2)
- single AZ
- gp2:io increases if the disk size increases .
- io1: can increase io independently.
- To migrate an EBS volume across AZ
- take snapshot
- restore snapshot to another AZ
- EBS backups use io, and you shouldn't run them while your app is handling lot of traffic.
- By default: Root EBS volumes of instances get terminated when the EC2 instance gets terminated. (you can disable that)
EFS
- Goal: simplify setting and managing shared file storage in cloud env.
- Main purpose is mounting 100 of Linux ec2s across AZ's
- more expensive than EBS
- EFS share websites files (WordPress)
- can leverage EFS-IA for cost savings.
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Instance Store
- I need max iops
- useful when data is not critical & is replaceable
- Good for buffer, cache , scratch data, temporary content.