Choosing Between S3 Standard vs Glacier ​

🔍 Overview: S3 Standard vs Glacier storage classes ​

S3 Standard (and Standard‑IA) ​

• Purpose: Frequent or predictable access.
• Access latency: Milliseconds.
• Durability: 99.999999999% (“11 nines”) (AWS Documentation, cloudwithdj.com)
• Availability: ~99.99% (Standard), ~99.9% (Standard‑IA) (AWS Documentation)
• Cost: Higher per‑GB; minimal or no retrieval fees. Standard‑IA cheaper storage but charges per retrieval.
• Minimum durations: None for Standard; 30 days minimum for Standard‑IA/One‑Zone‑IA (AWS Documentation)

Glacier Storage Classes (within S3) ​

Three archival tiers, each offering the same 11‑nines durability as S3 Standard (AWS Documentation).

• Storage cost: up to ~90% lower vs Standard (e.g. ~$0.004 /GB/mo) (Medium)
• Retrieval cost: charged per GB and request; faster tiers cost more (Wikipedia)
• Deletion charges: deleting objects before minimum duration still bills for full minimum term (AWS Documentation)
• Object size note: Glacier Instant requires ≥ 128 KB minimum (billed as 128 KB if smaller) (AWS Documentation)

✅ When to Use Which ​

Use S3 Standard or Standard‑IA when ​

• Data is accessed frequently or predictably (Standard: > monthly; IA: ~monthly).
• Immediate, high‑performance access is required.
• You want no additional retrieval latency or fees.

Use Glacier Instant Retrieval when ​

• Data is rarely accessed (e.g. quarterly or less), but must be available instantly if needed.
• Example: medical images, satellite imagery, media archives that might be served dynamically (AWS Documentation, Amazon Web Services, Inc.)
• Cost‑sensitive vs Standard‑IA for low access frequency.

Use Glacier Flexible Retrieval when ​

• Data access is very infrequent (once or twice a year).
• Retrieval delays of minutes to hours are acceptable (Expedited: 1–5 min; Standard: 3–5 h; Bulk: 5–12 h) (Amazon Web Services, Inc., Reddit, AWS Documentation)
• Use case: backups, disaster recovery, audit logs.

Use Glacier Deep Archive when ​

• Data is archived for long-term compliance (e.g. 7–10 years) or rarely needed (< once/year).
• Lowest possible storage cost outweighs retrieval latency (makes sense if you can wait 12‑48 hours) (Amazon Web Services, Inc., AWS for Engineers, cloudwithdj.com)
• Ideal replacement for tape libraries, regulatory archives, digital preservation.

⚙️ Lifecycle & Cost Considerations ​

• Automatically transition objects from Standard to Glacier via S3 Lifecycle policies based on age, tags, etc.
• Transition into Glacier has no minimum wait time, but billing still honors the 90/180‑day minimum (Medium, Reddit).
• Lifecycle transitions cost per request, especially when transitioning many small objects. Sometimes batching small files (e.g. zipping) helps (Reddit).

🧠 Quick Use‑Case Scenarios ​

• Website assets (images/videos): S3 Standard (low latency, frequent use).
• Monthly backup archives: Standard‑IA or Glacier Instant if access needs are rare but quick.
• Yearly audit logs or compliance data: Glacier Flexible Retrieval – cost effective with some delay.
• Multi-year retention archives (e.g. legal, financial): Glacier Deep Archive — ultra‑low cost, slow access is acceptable.

🧩 Summary Comparison ​

• Access frequency & latency: Standard (frequent/millisecond) → Instant Glacier (rare/millisecond) → Flexible (rare/minutes–hours) → Deep Archive (very rare/hours).
• Storage cost: Standard > Standard‑IA > Instant Retrieval > Flexible Retrieval > Deep Archive.
• Retrieval cost & delay: Standard has none; Glacier tiers trade cost for delay.

✔️ Recommendation Tips ​

• Define your data by access pattern, latency requirement, frequency of retrieval, and retention policy.
• Use S3 Lifecycle rules to automatically tier data over time.
• Monitor retrieval volumes and sizes to avoid surprising retrieval costs (especially for large restores).
• Batch small files to minimize request count and extra overhead.