WAR: EBS Volumes Attached To Stopped EC2 Instances

The AWS Well-Architected Framework emphasizes managing your cloud resources efficiently to optimize costs. While the Framework doesn't have a rule specifically addressing EBS volumes attached to stopped EC2 instances, it aligns with the Cost Optimization Pillar and the principle of CO.2: Rightsizing. This principle focuses on using resources efficiently to avoid unnecessary costs.

Here's a breakdown of the implications of keeping EBS volumes attached to stopped EC2 instances:

EBS Billing and Stopping EC2 Instances:

• EC2 Instance Costs: When you stop an EC2 instance, you are no longer charged for the hourly compute resources. This can lead to significant cost savings, especially for long-running instances.
• EBS Volume Costs: However, even when an EC2 instance is stopped, EBS volumes attached to it remain operational and continue to incur storage charges. You are billed based on the provisioned storage size (in GiB-months) of your EBS volume.

Impacts of Attached EBS Volumes on Stopped Instances:

• Unnecessary Costs: Keeping EBS volumes attached to stopped instances can lead to wasted spending if the data within those volumes isn't actively needed.

Alternative Approaches:

• Detach EBS Volumes: For stopped EC2 instances where the data is not required immediately, consider detaching the EBS volumes. This stops billing for the EBS volume while the instance remains stopped. You can then reattach the volume when you need to restart the instance.
• EBS Snapshots: If you need to keep a persistent copy of your data but don't require immediate access, you can create an EBS snapshot of the volume. Snapshots are stored in S3 and are significantly cheaper than active EBS volumes.
• Instance Termination and EBS Volume Backup: If the stopped EC2 instance is no longer required, and you only need to preserve the data on the EBS volume, consider terminating the instance. Ensure you have a backup of the EBS volume using snapshots before terminating the instance.

Making Informed Decisions:

The decision of whether to keep EBS volumes attached to stopped EC2 instances depends on your specific needs:

• Data Access Frequency: If the data on the EBS volume is frequently needed, keeping it attached might be necessary for faster access when restarting the instance.
• Backup Strategy: If you have a robust backup strategy using EBS snapshots, detaching volumes from stopped instances becomes a more viable option.
• Cost Optimization Goals: Carefully evaluate the cost implications of keeping EBS volumes attached versus detaching them or using snapshots for backups.

Conclusion

By understanding the cost implications of EBS volumes attached to stopped EC2 instances and exploring alternative approaches like detaching volumes or using snapshots, you can optimize your cloud storage costs and adhere to the Well-Architected Framework's principles of cost-effective resource management.