Alternatives to minimize data transfer costs for backup solutions


A customer is experimenting a high data transfer cost when using Commvault backup solution. Commvault is deployed in an EC2 instance and is copying EBS snapshots to another S3 bucket, being all the resources in the same region.

According to S3 pricing documentation:

You pay for all bandwidth into and out of Amazon S3, except for the following: .. • Data transferred out to an Amazon Elastic Compute Cloud (Amazon EC2) instance, when the instance is in the same AWS Region as the S3 bucket. ...

Customer was not expecting any data transfer cost for the backup solution but they detect high costs associated to the concept EU-DataTransfer-Regional-Bytes

Maybe I'm missing something but I do not see why this cost is there, as this concept is related with The amount of data transferred from Amazon S3 to AWS resources within the same AWS Region but that message seems counterposed with the s3 pricing documentation.

Any clarification around that would be appreciated and also other options if this scenario really implies a high transfer cost.

1 Answer
Accepted Answer

When EC2 instance and S3 bucket are in the same region - customer needs to ensure they use VPC Gateway Endpoint for communication between the two. If VPC endpoint is not used - this will likely fall under the Regional (Inter-AZ) data transfer category. That's exactly what "EU-DataTransfer-Regional-Bytes" usage type tells us.

Note that the charge should not be on the S3 side, but you should see it linked to EC2, as the instance will be communicating with S3 via public endpoint / public IP address.

More info in the blogpost about VPC endpoints:

And documentation:

Check out EC2 pricing for more info about Data Transfer here (specifically section around Regional Data Transfer charges):

profile pictureAWS
answered 4 years ago

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