AWS Cloud Practitioner: Simple Storage Service (S3) 101

AWS Cloud Practitioner: Simple Storage Service (S3) 101

In this short series, I outline the notes that I took while preparing for the AWS Cloud Practitioner exam.

These are my personal notes that I have made while working through the A Cloud Guru exam practitioner course. They are in no way official notes from AWS.

I would advise you that if you do use my notes to help you revise for this exam, that you use them as a supplement to the most recent information in the White PapersExam Guide and go over your knowledge with practice exam papers.

Previous notes within this blog series:

S3 Basics

Simple Storage Service (S3) provides developers and IT teams with secure, durable, highly-scalable object storage.

It has a simple, easy to use, web services interface to store and retrieve any amount of data from anywhere on the web.

  • S3 is a safe Object-based storage for e.g. picture, text files, videos NOT databases, application or OS.
  • Size of files can be from 0 – 5TB.
  • Unlimited storage paid by the GB.
  • Stored in buckets (folders in the cloud).
  •  When you upload a file to s3 you’ll get a HTTP 200 code to show successful upload


  • can have sub-folders
  • have universal namespace e.g. url that can be accessed. Buckets need to be unique globally.
  • Example bucket url: s3-[region][bucketName]

S3 Fundamentals

  • Is A Simple Key-value object store

Objects consist of:

  • Key – name of object
  • Value – data of file (sequence of bytes)
  • Version ID (important for versioning)
  • Metadata – data about what you’re storing
  • Sub resources:
    • Access Control Lists
    • Torrent

Data consistency model for S3

  • Read after Write consistency for PUTS of new Objects (Immediate)

i.e. If you write a new file and read it immediately afterwards, you will be able to view that data.

  • Eventual Consistency for overwrite PUTS and DELETES (can take some time to propagate across multiple availability zones)

i.e. If you update an existing file or delete a file and read it immediately, you may get the older version or you may not. Changes to objects can take a little but of time to propagate.

S3 Basics

  • Built for 99.99% availability
  • Amazon guarantee 11 x 9s durability for S3 information
  • Tiered Storage Available
  • Lifecycle Management (manage which storage tier it goes into)
  • Versioning
  • Encryption (encrypt your files at rest)
  • Secure your data using Access Control Lists (file level) and Bucket Policies (bucket level)

S3 Storage Tiers/Classes

S3 Standard

  • Built for 99.99% availability
  • Amazon guarantee 11 x 9s durability for S3 information
  • Stored redundantly across multiple devices in multiple facilities
  • Designed to sustain the loss of 2 facilities concurrently

S3 – IA (Infrequently Accessed)

  • Amazon guarantee 11 x 9s durability for S3 information
  • For data accessed less frequently, but requires rapid access.
  • Lower fee than S3, but you are charged a retrieval fee.

S3 One Zone – IA

  • Amazon guarantee 11 x 9s durability for S3 information
  • Lower cost option for infrequently accessed data
  • Only available in one availability zone

S3 – Intelligent Tiering

  • Amazon guarantee 11 x 9s durability for S3 information
  • Uses ML looking at your usage patterns
  • Moves data to the most cost-effective access tier without performance impact or operational overhead (can move your data across the other 3 tiers)
  • Available from only one AZ

S3 Glacier

  • Amazon guarantee 11 x 9s durability for S3 information
  • Low cost storage
  • Used for archival only
  • Comes in the models: Expedited, Standard or Bulk.
  • Standard retrieval configurable from minutes to hours.

S3 Glacier Deep Archive

  • Amazon guarantee 11 x 9s durability for S3 information
  • Lowest storage class
  • Retrieval time of 12 hours

S3 Charges

Charged for:

  • Storage per GB
  • Requests
  • Storage Management Pricing
  • Data Transfer Pricing (transferring from one region to another)
  • Transfer Acceleration
    • Enables fast, easy and secure transfers of files over long distances between your end users and an S3 bucket.
    • Takes advantage of Cloudfront’s globally distributed edge locations (small data center close to the user).
  • Cross Region Replication
    • When an item has been uploaded to a primary bucket is replicated to a secondary bucket

Creating an S3 Bucket Exam Tips

  • S3 is a global service (available on every region)
  • Bucket names share a common name space. Their names must be unique.
  • You view the buckets globally but you can have buckets in individual regions
  • Contents uploaded to buckets are private by default
  • You can replicate the contents of one bucket to another automatically by using cross region replication
  • You can change the storage class (S3 Standard, S3 – IA, S3 One Zone – IA, S3 Intelligent Tiering, S3 Glacier, S3 Glacier Deep Archive) and encryption of your objects on the fly
  • Transfer acceleration can be used to upload your file to an edge location (via the region you set up your bucket for), then AWS will transfer the file to other locations. Disabled by default.

Creating A Website On S3 Exam Tips

  • You can use bucket policies to make entire S3 buckets public (instead of individually updating the permissions on each object within the bucket) by enabling “Edit public access settings” to make everything in a bucket public by default
  • You can use S3 to host only a static website e.g. .html. websites that require a database connection e.g. a WordPress site cannot be hosted on S3.
  • S3 scales automatically to meet your demand. Useful when there will be a large number of requests e.g. movie previews.
  • Recognise the url that a statically hosted website will use i.e.

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