Storage and data transfer pricing: CLF-C02 study notes and practice questions
What to know about Storage and data transfer pricing for the CLF-C02 exam, from the Billing, Pricing, and Support domain (12% of the exam guide), then 1 free question to test it. Part of the CLF-C02 study guide.
These questions ask what you pay for when you store and move data on AWS.
What drives storage costs
Service
You pay for
Amazon S3
Gigabytes stored (by storage class), requests (PUT, GET), retrieval for infrequent-access and archive classes, data transfer out, and optional features such as replication
Amazon EBS
Gigabytes provisioned per month (whether you use them or not), plus extra IOPS or throughput for some volume types, and snapshots
Amazon EFS
Gigabytes used, by storage class
Cheaper S3 classes have lower storage prices but charge for retrieval and have minimum storage durations, so they suit data you rarely read.
Data transfer
Direction
Charge
Into AWS from the internet
Free
Out to the internet
Charged per GB (the first 100 GB a month are free)
Between Regions
Charged per GB, on the sending side
Between Availability Zones in a Region
Charged per GB
Within one Availability Zone over private IP addresses
Free
From AWS to CloudFront
Free; CloudFront charges for delivery to users
Ways to lower the bill
S3 Lifecycle rules move objects to cheaper classes over time.
S3 Intelligent-Tiering moves objects automatically when access patterns are unknown.
CloudFront can lower data transfer out costs and speeds up delivery.
Delete unused EBS volumes and old snapshots, which keep billing.
Tools
The AWS Pricing Calculator estimates costs before you build; the Billing console and Cost Explorer show what you are spending.
Common traps
Thinking uploads cost money. Data in is free.
Thinking EBS bills only for used space. EBS bills for the provisioned size.
Choosing Glacier for data read every day. Retrieval fees make it more expensive.
A company copies large nightly database backups from its application in the London Region (eu-west-2) to a backup account in the N. Virginia Region (us-east-1).
Finance wants to know which side of the transfer is charged.
How is this inter-Region data transfer billed?
Choose one answer.
AA. Both Regions charge, once when data leaves and again when it arrives
BB. Only data leaving the source Region is charged; data arriving is free
CC. Transfers between AWS Regions are always free, because they stay on the AWS network
DD. Only the destination Region charges, because it stores the new copy
Show the answer and explanation
Answer: B
A. Wrong: Data arriving in a Region is not charged. Only the outbound side carries a data transfer charge, so there is no second charge.
C. Wrong: Data moving between Regions is not free, even though it stays on the AWS network. The outbound side is billed by the source Region.
D. Wrong: The destination Region does not charge for incoming data. The transfer charge applies to data leaving the source Region.
Explanation
Inter-Region data transfer is charged on the outbound side, in the source Region. Data transferred into the destination Region has no transfer charge, although storing the copy is billed separately.
Want more on Storage and data transfer pricing? The 5 full-length practice sets have 5 more Storage and data transfer pricing questions, 325 in all, none of them in the free exam. One payment of $14.99, no subscription. See the practice sets →