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Zorluk: OrtaManaging Storage and Data Transfer Costs

A company runs a high-performance compute (HPC) cluster on Amazon EC2 instances in private subnets across two Availability Zones (`us-west-2a` and `us-west-2b`). The instances continuously read and write shared datasets on an Amazon EFS file system in the same Region, processing approximately 150 TB150\text{ TB} of data per month. A review of the monthly AWS bill reveals high Inter-AZ Data Transfer charges for EFS access, despite the EFS file system having mount targets in both Availability Zones. Investigation reveals that the EC2 instances are mounted to the EFS file system using the static IP address of the mount target in `us-west-2a` to simplify configuration management. Which of the following changes will minimize the data transfer costs while maintaining the required file sharing capability?

  1. A
    Configure a single NAT Gateway in `us-west-2a`, and update the route tables of both private subnets to route all EFS-destined traffic through this NAT Gateway.
  2. B
    Deploy an AWS Transit Gateway, associate the VPC subnets, and configure transitive routing using appliance mode across both Availability Zones to load-balance traffic to the EFS mount targets.
  3. Configure the EC2 instances to mount the EFS file system using its default DNS name rather than a static IP address, and ensure that DNS resolution is enabled in the VPC.Cevap
  4. D
    Purchase EC2 Instance Savings Plans to cover the Inter-AZ data transfer fees, and migrate the EFS datasets to an Amazon S3 bucket with a lifecycle policy to archive data to S3 Glacier Flexible Retrieval.

Cevap

Configure the EC2 instances to mount the Amazon EFS file system using its default DNS name instead of a static IP address, ensuring DNS resolution is enabled in the VPC.
Mounting the EFS file system using its DNS name (e.g., `file-system-id.efs.aws-region.amazonaws.com`) ensures that DNS queries resolve to the IP address of the mount target in the client's local Availability Zone. This local resolution keeps the data transfer within the same Availability Zone, eliminating Inter-AZ data transfer costs.

Adım Adım Çözüm

1
Identify the cause of the Inter-AZ data transfer charges.
The EC2 instances in `us-west-2b` are mounting the EFS file system using the mount target's IP address located in `us-west-2a`.
Mounting a resource across Availability Zones using a hardcoded IP address bypasses local AZ routing, forcing all traffic from the other AZ to traverse AZ boundaries and incur inter-AZ charges.
2
Select a mechanism to resolve EFS endpoints locally.
Configure EFS mounts using the file system's default DNS name.
When DNS resolution is enabled in the VPC, the EFS DNS name automatically resolves to the IP address of the local EFS mount target within the client's Availability Zone, keeping traffic local.
3
Evaluate and eliminate alternative options based on cost and functional requirements.
Eliminated options using NAT Gateways or Transit Gateways due to high data processing fees, and S3 Glacier due to performance mismatch.
NAT Gateway and Transit Gateway incur significant hourly and per-GB data processing fees, and S3 Glacier is inappropriate for real-time read/write datasets.

Anahtar Kavram

Local Availability Zone DNS resolution for Amazon EFS mount targets minimizes inter-AZ data transfer costs.
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Konular

Managing Storage and Data Transfer Costs