ContentsAuthorVisit Press
Lesson 31

Amazon S3 Object Storage

Buckets, storage classes, lifecycle policies, and pricing

1. What Is Amazon S3?

Amazon Simple Storage Service (Amazon S3) is managed object storage built to store and retrieve any amount of data from anywhere. It is one of the most heavily tested services on the CLF-C02 exam.

Core idea: S3 stores data as objects inside buckets. Each object can be up to 5 TB. Buckets have globally unique names and are associated with a specific AWS Region.

S3 is designed for 11 9s of durability (99.999999999%). By default, data is redundantly stored across multiple facilities and multiple devices within the selected Region. You do not provision capacity; storage scales automatically and you pay only for what you use.

2. Buckets, Objects, and URLs

ConceptDescription
BucketA logical container for objects. Bucket names must be globally unique across all of AWS and DNS-compliant.
ObjectComposed of data and metadata. Almost any file type can be stored: images, videos, logs, backups.
RegionWhen you create a bucket, you choose a Region. Data is redundantly stored across multiple facilities in that Region.
AccessObjects are accessible over HTTP/HTTPS via a URL. You can also access S3 privately through a VPC endpoint.
Exam tip: By default, none of your S3 data is shared publicly. Access is controlled through IAM policies, bucket policies, and per-object access control lists (ACLs).

3. S3 Storage Classes

S3 offers multiple storage classes optimized for different access patterns. The exam frequently presents a scenario and asks which class is most cost-effective.

Storage ClassBest ForKey Characteristics
S3 StandardFrequently accessed data: cloud applications, dynamic websites, content distribution, big data analytics.11 9s durability, four 9s availability, low latency, high throughput. No retrieval fees.
S3 Intelligent-TieringLong-lived data with unknown or unpredictable access patterns.Automatically moves objects between frequent and infrequent access tiers. Small monthly monitoring fee per object. No retrieval fees or tier-movement fees.
S3 Standard-IAData accessed less frequently but requiring rapid access when needed: long-term backups, DR files.Same durability as Standard, three 9s availability. Lower storage cost but per-GB retrieval fee.
S3 One Zone-IAInfrequently accessed data that is easily re-creatable or already replicated elsewhere: secondary backup copies.Stores data in a single AZ (not three). Lower cost than Standard-IA. Good for re-creatable data.
S3 GlacierData archiving with retrieval times from minutes to hours.Very low cost. Three retrieval options: Expedited (1-5 min), Standard (3-5 hours), Bulk (5-12 hours).
S3 Glacier Deep ArchiveLong-term retention and digital preservation for regulatory compliance (7-10+ years).Lowest-cost S3 storage. Retrieval within 12 hours. Magnetic tape replacement.

Storage Class Decision Framework

Is the data accessed frequently? Yes → S3 Standard.

Are access patterns unknown or unpredictable? Yes → S3 Intelligent-Tiering.

Is it infrequently accessed but must be available instantly when needed? Yes → S3 Standard-IA.

Is it easily re-creatable or a secondary copy stored in only one AZ? Yes → S3 One Zone-IA.

Is it archival data with defined retrieval time needs? Yes → S3 Glacier (minutes to hours) or Glacier Deep Archive (lowest cost, 12 hours).

4. Lifecycle Policies

S3 lifecycle policies automate the transition of objects between storage classes or their deletion based on age. This reduces cost by moving data to cheaper classes as it becomes less important over time.

Example lifecycle flow:

  1. Upload a video preview to S3 Standard for immediate access.
  2. After 30 days, transition to S3 Standard-IA because access drops off.
  3. After 60 days, move to S3 Glacier for long-term archiving.
  4. After 1 year, delete the object automatically.
Exam tip: Lifecycle policies can be set per object or per bucket. They manage movement automatically without manual intervention.

5. Common Use Cases

  • Application assets: Shared storage for user-generated media, server logs, or files that any EC2 instance can access.
  • Static web hosting: Host HTML, CSS, JavaScript, and image files directly from a bucket.
  • Backup and disaster recovery: High durability makes S3 ideal for backups. Cross-Region replication can copy data to another Region automatically.
  • Big data staging: Store raw datasets before processing with analytics tools.
  • Software delivery: Host application binaries that customers download.

6. Pricing Basics

S3 pricing has four main components. The exam tests whether you know what is free versus what incurs charges.

ComponentCharged?Notes
StorageYesPer GB per month. Rate varies by storage class.
RequestsYesPUT, COPY, POST, LIST, and GET requests have different rates.
Data transfer INNoUploading data into S3 is free.
Data transfer OUTYesTransferring data out of the S3 Region incurs charges. Transfer to CloudFront or EC2 in the same Region is free.
Memory trick: In is free; Out costs money. Think of S3 like a hotel: checking in is free, checking out has a fee.

7. Quick Quiz

Test Your Understanding

Select one answer per question. You will receive immediate feedback.

1. A company stores monthly backups that are rarely accessed but must be retrievable within seconds if a disaster occurs. Which S3 storage class is most cost-effective?
2. Which S3 storage class automatically moves objects between access tiers based on changing access patterns without retrieval fees?
3. A healthcare company must retain patient records for 10 years to meet regulatory requirements. The records will likely be accessed once or twice per year. Which storage class is the best fit?
4. An application generates thumbnail previews that are heavily accessed for 30 days, then rarely accessed afterward. The company wants to automate cost reduction. What should they use?
5. Which statement about S3 bucket names is correct?
6. A company wants to store secondary backup copies of on-premises data in AWS at the lowest possible cost. The data is easily re-creatable. Which storage class should they choose?
7. Which of the following S3 operations incurs a charge?
8. What is the maximum size of a single object that can be stored in Amazon S3?
Progress: 0/8 correct (0%). Answer all questions to see the final recommendation.
Primary Source: AWS Academy Module 7: Storage (module-7.txt).
Ask your teacher: If you are unclear on when to choose Standard-IA versus One Zone-IA, or how lifecycle policies automate transitions, ask before continuing. The exam frequently pairs a scenario with a cost-optimization goal.
Last updated: June, 2026© 2026 Shahriar Ahmed ShovonCredits