Lesson 195 · AWS Learning Path

AWS 195: Storage and data-transfer cost optimization

Anil Jalela · Published Jan 6, 2026 · 8 min read

Why this lesson matters

Optimize from lifecycle and packet path: class, retention, requests, IOPS, throughput, snapshots, retrieval, AZ crossings, internet egress, NAT, and endpoints.

What you will be able to do

By the end, you can:

• explain storage and data-transfer cost optimization in plain language;
• locate the current service controls in the AWS Management Console;
• run the matching CloudShell or AWS CLI queries and explain every important field;
• draw the identity, network, data, failure, and monitoring path;
• choose the service from requirements and reject it when those requirements are absent;
• diagnose a failed or misleading result from evidence;
• state the cost owner and prove cleanup or a no-create result.

Before you start

• Use a personal AWS account only when its owner has approved the lesson. Do not use the root user for daily work.
• CloudShell is the default command environment. AWS028 explains CloudShell; AWS029 and AWS030 explain local AWS CLI installation and profiles.
• The course example Region is ap-south-1. Global services and services with a required control Region are called out in their commands.
• Run aws sts get-caller-identity privately. Redact the account number before sharing evidence.
• Never paste access keys, passwords, secret values, private object data, presigned URLs, or full account-specific ARNs into a submission.
• This is a no-create lesson. Every Console action and AWS CLI command is read-only. Create the practical artifact locally.
• Console wording can change. Use the Console service search if a menu label has moved, then confirm the current field in the official documentation.

The core model

How the request flows

+-----------------------------+
|  Data age and traffic path  |
+-----------------------------+
              |
              v
+--------------------------------------+
|  Storage or network price dimension  |
+--------------------------------------+
                   |
                   v
+-----------------------------------------+
|  Safe lifecycle or architecture change  |
+-----------------------------------------+
                    |
                    v
+-----------------------------------------------+
|  Performance, restore, and cost verification  |
+-----------------------------------------------+

Optimize from the byte and request path

Storage price per GB is only one term. Total cost can include provisioned capacity, requests, IOPS/throughput, retrieval, early deletion, lifecycle transitions, replication, backup copies and data transfer. Draw where each byte is created, stored, read, copied and deleted, including AZ/Region/account/internet boundaries.

Storage decisions

Deleting a source volume does not delete retained snapshots; AMIs, orphan snapshots, unattached volumes, old RDS snapshots and backup vault recovery points need ownership. Snapshot size is changed blocks, not necessarily volume provisioned size. Never delete from age alone - map dependency, retention and restore evidence.

Lifecycle transitions can cost more for tiny/short-lived objects due to per-request charges, minimum storage duration and minimum billable object size. Model object count and churn, not just TB. Compression, columnar formats and partition pruning can reduce both storage and scan/query transfer, but require workload-compatible CPU and retrieval behavior.

Data-transfer topology

Common cost boundaries include internet egress, inter-Region transfer, cross-AZ paths, NAT Gateway hourly/data processing, interface endpoint hourly/data processing, Transit Gateway processing, replication and CDN viewer/origin transfer. Prices and exceptions are service/direction/Region specific; verify current pages.

Optimization patterns:

• Keep chatty application/database tiers in the same AZ only when that does not undermine required AZ resilience; otherwise budget cross-AZ traffic.
• Deploy zonal NAT gateways and route each private subnet to its local NAT to avoid cross-AZ hairpinning; compare NAT with gateway endpoints for S3/DynamoDB and interface endpoints for supported services.
• Use CloudFront caching/compression/origin shielding when it reduces origin requests/bytes and meets freshness/security needs.
• Avoid repeatedly moving bulk data across Regions; compute near data where latency, sovereignty and resilience allow.
• Inspect load balancer cross-zone behavior, Kubernetes topology, EFS mount targets and centralized inspection/TGW paths.

A VPC endpoint is not automatically cheaper: compare hourly endpoints per AZ, bytes and operational/security value against NAT path. A centralized inspection architecture can add TGW, firewall and cross-AZ processing by design; calculate both directions.

Measurement and safe change

Use Cost Explorer/CUR usage types to locate spend, then correlate with CloudWatch bytes/requests, S3 Storage Lens, EBS metrics, VPC Flow Logs and resource inventory. Test one change, measure performance/durability/RTO effects, and preserve rollback. Cost optimization that violates retention or removes recovery capacity is an architecture failure.

Architecture decision table

AWS Management Console, step by step

Sign in with the normal non-root learning identity. Write the expected starting state before opening the service.

1. Use the Console service search and open S3 Storage Lens or Metrics, EC2 volumes and snapshots, VPC NAT gateways and endpoints, Cost Explorer; confirm the account and Region before reading the page.
2. Inspect the supplied or owned resource's status, configuration, permissions, networking, encryption, monitoring, tags, and dependencies without changing it.
3. Open the related metrics, logs, events, or history view and record one timestamped signal that would prove or disprove the expected behavior.
4. Return to the resource list, clear filters, and record the final inventory. On the read-only track, do not choose Create, Save, or Delete.

CloudShell and AWS CLI, step by step

Start with a known caller and Region:

export AWS_DEFAULT_REGION="ap-south-1"
aws sts get-caller-identity --query Arn --output text
aws configure list

Redact the account part of the ARN in shared evidence. Now run the topic queries:

aws s3api list-buckets --query 'Buckets[].Name' --output table
aws ec2 describe-volumes --query 'Volumes[].{Type:VolumeType,GiB:Size,IOPS:Iops,Throughput:Throughput,State:State}' --output table
aws ec2 describe-snapshots --owner-ids self --query 'Snapshots[].{Id:SnapshotId,GiB:VolumeSize,State:State,Started:StartTime}' --output table
aws ec2 describe-nat-gateways --query 'NatGateways[].{Id:NatGatewayId,State:State,Subnet:SubnetId}' --output table

Expected interpretation

Inventory supplies resource quantities. Real optimization requires access and age evidence, restore need, request profile, network flow, performance, owner, and safe deletion or migration tests.

Practical work

Analyze ten cost findings: stale snapshot, oversized gp3, log retention, S3 lifecycle, retrieval spike, cross-AZ NAT, missing S3 endpoint, duplicate data, idle public IPv4, and global transfer. Rank savings against risk.

Diagnose this topic from its own evidence

• S3 bill rises after lifecycle: inspect transition/retrieval requests, minimum duration/size, object count and restore pattern.
• NAT dominates: identify source/destination bytes in flow logs, local-AZ routing and endpoint/CDN alternatives.
• Data transfer usage type unexplained: map service, direction, source/destination AZ/Region and both legs of intermediaries.
• Snapshot cost persists: inventory AMI/backup dependencies, incremental lineage and retention before deletion.
• Cheaper tier harms application: compare retrieval latency/fees, throughput and RTO against requirement and roll back.

Cost and cleanup

Requests, running capacity, storage, logs, data transfer, retained state, and optional features must be priced for the exact design.

Knowledge check

1. What operational purpose is this lesson solving?

Expected direction: Optimize from lifecycle and packet path: class, retention, requests, IOPS, throughput, snapshots, retrieval, AZ crossings, internet egress, NAT, and endpoints.

1. Which scope or ownership boundary must be proved first?

Expected direction: The learner must identify the account and Region scope, resource boundary, identity path, data or network path, failure behavior, observability, and cleanup ownership for Storage and data-transfer cost optimization.

1. What evidence is strong enough to accept the result?

Expected direction: Success means the Console fields, CLI result, workload behavior, monitoring evidence, and architecture claim agree. An available state alone is not enough for Storage and data-transfer cost optimization.

1. Which tempting design or shortcut must be rejected?

Expected direction: Avoid deleting backups from age alone, moving hot data to archival class, or centralizing traffic without cross-AZ analysis.

1. Which cost dimensions and retained resources need an owner?

Expected direction: Requests, running capacity, storage, logs, data transfer, retained state, and optional features must be priced for the exact design.

Lesson acceptance

• Produce a per-byte/per-request architecture with every charging boundary.
• Model lifecycle using object count, size, duration, transitions, retrieval and restore time.
• Right-size EBS/storage performance separately from capacity.
• Compare NAT, gateway/interface endpoints, CDN and centralized-network paths quantitatively.
• Implement a measured reversible optimization without weakening durability, security or recovery.

Official sources

• S3 cost optimization
• Data transfer charges