Amazon S3 stands for Simple Storage Service

It is an object storage service

Used to store unlimited data

Highly durable and scalable

Durability – 11 9’s (99.999999999%)

S3 is designed for extremely high durability, meaning data loss is highly unlikely.

Availability – 4 9’s (99.99%)

S3 ensures high availability, so data is accessible most of the time

Object Storage

Data stored as objects

Each object has

Data

Metadata

Unique ID

Example

Amazon S3

Data stored in blocks

Used with servers

Requires operating system

Example

Amazon EBS(Elastic block store)

Data stored in folder structure

Shared access

Works like traditional file systems

Example

 Amazon EFS (Elastic File System)

Key Points

Define rules to automate storage management

Move files to cheaper storage classes based on age

Reduce costs by automatically deleting old files

Example

A company stores daily backup files in S3,
moves files older than 30 days to Glacier,
and deletes them after 90 days to save money.

Example (Public Read Bucket Policy)

Read

Write

Helps in data security

Grant / deny access to users

Control at bucket and object level

Manage permissions for multiple accounts

Uploads large files in parts instead of a single upload

Each part is uploaded independently and in parallel (faster performance)

If a part fails, only that part is re-uploaded, not the whole file

Best for large files (100 MB to TBs) and unstable networks

After all parts upload, S3 combines them into one object automatically

A company uploads a 5 GB backup file to S3. Instead of one long upload, it splits into parts → uploads faster and resumes easily if interrupted

Data encrypted

At rest

In transit

Key Benefits:

Ensures data security and compliance

Uses strong encryption algorithms (AES-256)

Keys managed by AWS KMS or customer

Real World Example

A company keeps a copy of important files in another AWS region so data remains safe and available even if one region fails.