Archive Old EBS Volume Snapshots

Opportunity Name:

Archive Old EBS Volume Snapshots

AWS Resource Type:

EBS Snapshots

Opportunity Description:

This opportunity identifies old EBS snapshots that can be archived to a cheaper storage tier.

Criteria for identifying the opportunity:

Two types of snapshots are archived:

• Snapshots older than 30 days that are the most recent snapshot taken of an EBS volume
• Snapshots that are not the most recent snapshot taken and include >25% “unreferenced” data (i.e., data that is not referenced by other snapshots)

Because EBS snapshots are incremental (i.e., they only include the delta from the most recent snapshot taken), other snapshots can reference new data created in the snapshot.  It is also possible for the snapshot to include deleted data in future snapshots, which results in that data becoming “unreferenced”.  When a snapshot includes >25% unreferenced data, it becomes cost-effective to archive it.

There are also several snapshots excluded if any of the following criteria are met:

• Any snapshots managed by the Amazon Data Lifecycle Manager or AWS Backup
• Any snapshots shared with other AWS accounts
• Any snapshots that have Fast Snapshot Restore enabled

Potential savings (range in % on annual basis):

Cost savings are dependent on the type of data and data usage patterns of each EBS volume. 

For example, a snapshot with 50% unreferenced data would result in a 25% cost saving, while a snapshot with 75% unreferenced data would result in a 50% cost saving.  The maximum cost savings is 75% assuming a snapshot contains 100% unreferenced data.

What happens when the Fixer is executed?

The fixer modifies the snapshot attributes such that the snapshot is archived and moved to the archived storage tier.

Is it possible to rollback once CloudFix implements the fixer?

Yes, you can restore an archived snapshot back to a normal snapshot at any time.  Depending on the snapshot size, it might take up to 72 hours.  Once restored, you can use the snapshot to recover an EBS volume.  See the AWS documentation for more information.   

Note that the minimum archive period is 90 days, meaning if you restore an archived snapshot before the minimum period of 90 days, you will still be billed for the remaining days in the archive tier.

Can CloudFix implement the fix automatically once I accept the recommendation?

Yes.

Does this fix require downtime?

No.

Additional Resources:

• CloudFix Knowledge Base
• Guidelines and best practices for archiving snapshots