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AWS S3 – Overview

AWS S3 or Simple Storage service is a place to simply and securely collect, store, and analyze your data at a massive scale. Amazon S3 is object storage (Movies,  built to store and retrieve any amount of data from anywhere

S3 Basics

Files are stored in buckets. Buckets are folders that have a universal namespace or a URL so it must be globally unique.

A bucket has the link such as https:/<bucket Name>

You will receive an HTTP 200 code when an upload is successful.

Read after write consistency for PUTS of new Objects. This means we can read a file immediately after a file is uploaded

Eventual Consistency for overwrite PUTS and DELETES this means that when a file is changed it takes times so when a change across all availability zones and as such changes may not be seen depending on how fast you access it.

What makes up S3

Object based – Files

  1. Key (this is simply the name of the object)
  2. Value (this is simply the date and is made up of the sequence of bytes)
  3. Version ID
  4. Metadata (data about your data)
  5. Subresources
    1. Access Control Lists
    2. Torrent


  • Build for 99.99% Availability for the S3 and Amazon Guarantee 99.9% availability.
  • Amazon Guarantees 99.999999999% durability for S3 information (11 9’s)
  • Tiered storage available
  • lifecycle management
  • versioning
  • encryption
  • secure data using Access control lists and bucket Policies

Storage Tiers/Classes

S3 Standard: 99.99% availability, 99.99999999% durability, stored redundantly across multiple devices in multiple facilities and is designed to sustain the loss of 2 facilities concurrently.

S3 – IA: (Infrequently Accessed): For data that is accessed less frequently, but requires rapid access when needed. A lower fee that standard, but you are charged a retrieval fee.

S3 one zone – IA: A lower-cost option for infrequently accessed data, but does not have multiple AZ data resilience

Glacier: Very cheap, but used for archival only. Expedited, Standard or Bulk. A standard retrieval time takes 3-5 hours

What are we charged for

  • Storage – Per GB bases
  • Requests – The number of times a request is pulled/access
  • Storage Managment – Charged for the metadata or who has access to it
  • Data Transfer Pricing – Moving data
  • Transfer Acceleration – Transfer or files over long distance between your end users and an S3 bucket. EG, A user uploads files to an Edge location and then that is uploaded to the main AZ.

Things to remember

  • Storage is Object-based: Allows you to upload files
  • Files can be stored from 0Bytes to 5TB
  • Unlimited storage limits
  • Files stored in Buckets
  • Buckets are universally namespaced: Names must be unique globally
    • https://<Region><BucketName>
  • Read After Write Consistency for PUTS of new objects
  • Eventual Consistency for overwrite PUTS and DELETES: Changing a file takes time
  • Storage Classes/Tires
    • Standard: Durable, immediately available
    • AI: Durable, immediately available, infrequently accessed
    • One Zone – IA: Cheapest IA but no redundancy
    • Glacier: Long-term storage taking 3-5 hours to access
  • Core Fundamentals:
    • Key(name)
    • Value(data)
    • Version ID
    • Metadata
    • Subresources
  • Store Objects only – not meant for database or OS
    • Uploading gives an HTTP 200 when a successful upload
  • Read the FAQ


For more on AWS please see the Table of contents here.

An overview of the associates exame click here.


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