EC2 application instances and an RDS database are in different Availability Zones in the same Region.
The application performs a large volume of reads and writes, so the estimate must include relevant transfer items.
Which charge might need to be included in the estimate?
Traffic between Availability Zones can be charged as Regional Data Transfer even when both zones are in the same Region. Placement and path should be included in a high-volume estimate.
Detailed explanation
Some same-Region paths, including traffic between Availability Zones, can be chargeable.
Some same-Region paths, including traffic between Availability Zones, can be chargeable.
Multi-AZ improves availability; it is not a blanket waiver for data transfer charges.
Multi-AZ improves availability; it is not a blanket waiver for data transfer charges.
Data crossing Availability Zones in one Region can be subject to Regional Data Transfer charges depending on the services and direction.
Data crossing Availability Zones in one Region can be subject to Regional Data Transfer charges depending on the services and direction.
Transfer pricing also depends on path, services, Region, and direction.
Transfer pricing also depends on path, services, Region, and direction.
Check official documentation
Compare the following points with the official documentation.
AWSのリージョナルデータ転送の説明と、利用するサービスの料金ページを確認する。
Official references
What to confirm
リージョン内でもAZ間転送を別の料金経路として見積もれる。
Key points
- Inter-AZ transfer
- Regional Data Transfer
- Placement and path
Notes
- Environment:
- Data transfer pricing and free tiers can change by service and Region. Check the current AWS pricing page before implementation.
Foundation review
Region versus AZ
A single Region contains multiple Availability Zones, and crossing an AZ can have different pricing and availability implications.
Availability and cost
Distributing components can improve resilience but high-volume cross-AZ traffic should be included in the cost review.