[AWS] S3 Storage Classes and Versioning

S3 Storage Classes (Storage Tier) – cost, durability, and availability – can be changed manually or using lifecycle policies.

Object Durability: The percentage over a one-year period that an object in S3 will not be lost.
Object Availability: The percentage over a one-year period that an object in S3 will be accessible.

Tier	AZ Replication	Availability	Lifecycle Transition	Features
Standard	3+	99.99 %	Yes	For frequently accessed data
Standard IA	3+	99.9 %	Yes	Fast real-time access but less frequently (such as once a month)
One Zone IA	1		Yes	non-critical or reproducible data
Express One Zone	1	99.95 %	No	HIgh-performance, latency-sensitive, No Lifecycle transition
Intelligent Tiering	3+	99.9 %	Yes	For unknown access patterns
Glacier Instant Retrieval	3+	99.9 %	Yes	Ideal for data that is accessed once or twice per quarter (few tines a year) and that requires immediate access
Glacier Flexible Retrieval	3+	99.99 %	Yes	Backup and archive data that is rarely accessed.
Glacier Deep Archive	3+	99.99 %	Yes	Archive data that is very rarely accessed

S3 Classes

Glacier Flexible Retrieval
- Flexible retrieval
  - minutes ~ 12 hours
  - Expedited: 1 ~ 5 minutes
  - Standard: 3 ~ 5 hours
Glacier Deep Archive
- Retrieval time: ~12 hours
- Bulk Retrieval time: ~ 48 hours
Intelligent Tiering
- only for objects bigger than 128 kB
- for unknown or unpredictable access patterns
- A minimum 30 days before transitioning to IA storage tiers.
- After 30 days, objects that are not accessed are moved to the IA tier.

You are changed based on:

Tier	Retrieval Fee	Minimum Size Charge	Minimum Duration Charge	Features
Standard	No	N/A	N/A	Most expensive base fee
Standard IA	per GB retrieved	128 KB	30 days	Fast real-time access but less frequently (such as once a month)
One Zone IA	per GB retrieved	128 KB	30 days	non-critical or reproducible data
Express One Zone	No	N/A	1 hour	Cheaper than the Standard
Intelligent Tiering	No	128 KB	N/A	Automatic cost savings
Glacier Instant Retrieval	per GB retrieved	128 KB	90 days
Glacier Flexible Retrieval	per GB retrieved	N/A	90 days	Low cost
Glacier Deep Archive	per GB retrieved	N/A	180 days	Very low cost

S3 Pricing

Storage classes can be modified on the fly.

Lifecycle rules are added at a bucket level.
- Lifecycle rules can apply to buckets, prefixes, and tags. Also, they work with current or previous versions of an object.
Lifecycle automatically moves objects between the different storage tiers.
- You can add a rule to a bucket such as Standard -> Glacier -> Delete.
- Object must stay at least 30 days in S3 Standard before moving to IA or one zone IA. But you can transfer objects directly to Glacier at any time.

When the versioning is enabled, any modification of an object generated a new version of the original object.

Once enabled, S3 stores all versions of an object with previous permissions. It is a great backup tool.
Versioning is per bucket and is disabled by default.
Once the version is enabled on a bucket, it cannot be disabled – only suspended.

Versioning can use with MFA (Multi-Factor Authentication) Delete, which can provide additional security for accidental deletion or overwrite.

Limits
- 3,500 PUT/POST/DELETE operations per second per prefix
- 5,500 GET requests per second per prefix.

Introduce key randomness (random prefix) to spread load across multiple partitions.
- Prefix is what is between the bucket name and the object name in URL (folders and sub-folders).
- You can get better performance by spreading the reads across different prefixes.

When you use SSE-KMS for encryption, KMS has some limits (KMS has a region-specific quota).

Use multipart uploads (recommended over 100MB and required over 5GB) to increase upload performance.
Use S3 Byte-range fetches: download an object in parallel by specifying byte ranges or download the partial amount of file

Published by Pyongwon Lee