S3 Standard-IA: Lower Cost Storage with Immediate Retrieval for Infrequent Access

Ned
Ned Cloud Engineer
· Updated · 2 min read
S3 Standard-IA: Lower Cost Storage with Immediate Retrieval for Infrequent Access

The Problem

You have data in S3 Standard. Analysis shows 75% of it is rarely accessed after 30 days. The data must remain immediately accessible with the same high availability and resilience as S3 Standard. You want to cut storage costs.

The Solution

Transition data to S3 Standard-Infrequent Access (Standard-IA) after 30 days using a lifecycle policy.

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aws s3api put-bucket-lifecycle-configuration \
  --bucket my-data-bucket \
  --lifecycle-configuration '{
    "Rules": [
      {
        "ID": "MoveToIAAfter30Days",
        "Status": "Enabled",
        "Filter": {},
        "Transitions": [
          {
            "Days": 30,
            "StorageClass": "STANDARD_IA"
          }
        ]
      }
    ]
  }'

How It Works

S3 Standard-IA is designed for exactly this scenario — data you do not access often but need immediately when you do:

Feature S3 Standard S3 Standard-IA S3 One Zone-IA
Storage cost/GB $0.023 $0.0125 $0.01
Retrieval cost/GB Free $0.01 $0.01
Availability 99.99% 99.9% 99.5%
Durability 11 nines 11 nines 11 nines (single AZ)
AZ redundancy 3+ AZs 3+ AZs 1 AZ
Retrieval speed Milliseconds Milliseconds Milliseconds

The key points:

  • Same durability as S3 Standard (99.999999999%)
  • Same multi-AZ redundancy (3+ AZs)
  • Same retrieval speed (milliseconds)
  • 46% lower storage cost ($0.0125 vs $0.023 per GB)
  • Trade-off: small per-GB retrieval fee and slightly lower availability SLA (99.9% vs 99.99%)

Why Not the Alternatives?

S3 Glacier Deep Archive — Not immediately accessible. Retrieval takes 12-48 hours. Violates the “immediately accessible” requirement.

S3 One Zone-IA — Stores data in a single Availability Zone. If that AZ has an outage, data becomes unavailable. Does not provide the same high availability and resilience as S3 Standard. The question specifically requires matching S3 Standard’s resilience.

Move to One Zone-IA immediately — Two problems: (1) violates resilience requirements, and (2) data is frequently accessed during the first 30 days, meaning retrieval fees would offset storage savings.

Key Takeaways

  • S3 Standard-IA provides the same durability and multi-AZ resilience as S3 Standard
  • Storage cost is 46% lower; the trade-off is a per-GB retrieval fee
  • S3 One Zone-IA is cheaper but stores data in one AZ — it does not provide the same resilience
  • Always check if the requirement says “high availability” or “same resilience” — these exclude One Zone-IA
  • S3 Standard-IA has a 128 KB minimum object size and 30-day minimum storage duration
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