INTRODUCTION👋

Amazon's Simple Storage Service (S3) is a storage service for any amount of data in various use cases, including:

• static websites
• backups & archives
• data lakes
• IoT devices
• big data analytics

With S3's management features you're enabled to optimise the storage of and access to your data easily and in a fine-grained way.

BUCKETS🪣

Buckets are the most fundamental part of S3. Think about it as a folder on your local machine, but with unlimited storage and number of files.

A bucket needs a unique naming, not only within your account but globally.

Buckets can be configured in different ways, for example with dedicated access policies or encryption configuration.

Additionally, each file in a "bucket" is considered an object and can have its own metadata and configuration.

STORAGE CLASSES📁

Amazon offers different types of storages, which help you to find a good trade-off between availability and durability based on your access patterns and costs.

The types can be split into three major groups:

• Standard
• Infrequent Access (IA)
• Glacier

Additionally, there's the Intelligent Tiering storage class for data with unknown, changing or unpredictable access patterns.

STORAGE MANAGEMENT⚙️

S3 not only enables you to make use of different storage classes to reduce costs, but also offers additional management features like:

• Lifecycle Policies
• Object Locks
• Replication
• Batch Operations

Those features can help you for example to meet requirements due to regulations or compliance.

LIFECYCLE POLICIES🔄

Objects stored within your buckets sometimes do have changing requirements within their lifecycle. With Lifecycle Policies, you can automatically adapt to those requirements.

A lifecycle policy can contain multiple rules, which in turn specify actions when a group of objects match a certain condition is met.

There are two types of action:

• Transition - moving objects to another storage class
• Expiration - deleting objects

OBJECT LOCKS🔒

S3 also helps you to keep your data as safe as possible with Object Locks.

It allows you to store files using a Write-Once-Read-Many model.

You can choose between two different retention modes:

• Compliance - no deletes or overwrites possible for the duration of the retention period
• Governance - overwrites/deletes are only possible with specific rights

For a lot of use cases, it's necessary that files are not simply overwritten but only created with a new version, so that you can also rollback versions & can easily rollback to a previous state.

Example: your Terraform's infrastructure state files. S3 also got you covered here: you can enable versioning per bucket with a single option.

REPLICATION📋

With replication, you can asynchronously copy objects across S3 buckets. You're not bound to buckets that are owned by your account.

Replication helps you to easily create identical copies (including the metadata), e.g. to create redundancy for backups.

You can even:

• replicate the copy into a different storage class
• move them to a different ownership
• or store them in multiple AWS regions

BUCKET POLICIES🛡️

Bucket policy enable you to grant access permissions to your bucket and to the objects inside of it.

Policies are JSON-based and either allow or deny certain actions on a Resource for a given principal.

In the example, we...

• grant a CloudFront Origin Access Identity
• read permissions
• for all objects inside our target bucket

EVENT NOTIFICATIONS🔔

There are a lot of use cases that require triggering processes in the case of events happening at S3.

Prominent example: creating a thumbnail after an image was uploaded to a bucket.

S3 can send notification messages to different destinations like:

• SNS Topics
• SQS Queues
• Lambda Functions

and for different events, including:

• creation or deletion of objects
• lifecycle executions (e.g. expiration events)
• object tagging
• ACL PUTs

With this, we can easily cover our example: ObjectCreated events for objects with an image suffix at a specific bucket will trigger a Lambda function, which in turn will create a thumbnail for the uploaded image and upload it to another bucket.

BATCH OPERATIONS🛠️

With single API requests, you are able to manage billions of objects.

A batch job will execute a specified operation on every object that's included in the job description. Running jobs can be monitored programmatically or via the AWS console.

BLOCK PUBLIC ACCESS⛔

By default, new buckets and objects are not publicly accessible through the internet.

As users can modify bucket policies and object permissions, public access can be enabled.

With Block Public Access, account and bucket owners can easily setup centralized controls that are enforced regardless of how the resources are created.

VERSIONING🔖

For a lot of use cases, it's necessary that files are not simply overwritten but only created with a new version, so that you can easily rollback to a previous state.

Example: your Terraform's infrastructure state files. S3 also got you covered here: you can enable versioning per bucket with a single option.

⭐ Bonus: Versioning can be combined with Lifecycle Policies.

FREE TIER🎁

AWS' free tier for S3 includes:

• 5 GB of standard storage
• 20,000 GET requests
• 2,000 PUT requests

ℹ️ You'll be notified via e-mail when you're approaching the limits of the free tier.

PRICING💰

You're paying for storing objects, making requests against your buckets, data transfer & advanced features.

For storage & requests, the rates are highly vary based on the storage class.

Transfer charges are based on the source & destinations, e.g. from S3 to the Internet you'll pay $0.09 per GB but transfer from the Internet to S3 is free, as well as outgoing traffic from S3 to CloudFront.

As with other services, rates can vary also between regions.