=================================
AWS S3 (Simple Storage Service)
=================================

-> S3 is a storage service in AWS cloud.

-> S3 supports unlimited storage.

-> Using S3 we can store any amount of data from anywhere at anypoint of time.

-> S3 supports object based storage (files).

      One Object = One file

Note: We can store any type of file in s3 

  Ex: .txt, .mp4, .png, .jpeg, .doc, .pdf, .xls ......      


-> In S3, we need to create buckets to store objects (files)

Note: In one bucket we can store group of objects.

Note: Every bucket should have unique name.

-> When we create a bucket, end-point url will be generated to access bucket.

-> When we upload object into bucket, every object will get its own end-point url.


Note: By default, buckets and objects are private (we can them as public).


=================================
Static Website Hosting using S3
=================================

-> Website nothing but collection of web pages.

Ex: login page, regiter page, services, about us page, contact us page...

-> Websites are divided into 2 types

  1) static website

  2) dynamic website

-> The website which gives same response/content for all users is called as static website. 

-> The website which gives response based on user is called as Dynamic website.


=> Static websites we can deploy in 2 ways

  1) Create EC2 Linux VM and Install HTTPD Webserver and Deploy

  2) Deploy using S3 bucket


Step-1: Create s3 bucket with unique name

Step-2: Upload website files & folders into bucket with public read-access

Step-3: Enable Static website hosting (in bucket properties)

      index-document : index.html
      error-document : error.html

Note: After enabling static website hosting it generates end-point URL for our website.

Step-4: Access our website using website endpoint url.


===================
S3 Storage Classes
===================

=> Storage classes are used to specify how frequently we want to access our objects from S3.

=> At the time of uploading object into S3 bucket we can select storage class for that object.

=> We have several storage classes in s3 like below..

1) standard (default) : To access object more than once in a month

2) Intelligent - Tiering : Unknown access patterns

3) Standard-IA : Infrequent Accesed Data (Only once in month)

4) One Zone-IA : Stored in single availability zone (once in a month)

5) Glacier Instant Retrieval : Long Live Archieve Data
  (once in quarter -> Milli Seconds)

6) Glacier Flexible Retrieval : Once in a year (Minutes to Hours)

7) Glacier Deep Archieve : Less Than once in a year (Hours to download)

8) Reduced Redundency : Not Cost Effective (Not recommended)


============
Versioning
============

=> It is used to maintain multiple variants of same file.

=> By default versioning will be disabled for S3 bucket.

=> As versioning is disabled, when we upload file again it will override old file.

=> If we don't want to replace old objects from bucket then we can enable Versioning.

=> Versioning we will enable at bucket level and it is applicable at object level.

================
Object Locking
================

-> It is used to enable the feature WORM (Write once read many times) model.

-> We can enable object lock on versioning enabled buckets.

-> Object Lock will be enabled at bucket level and it is applicable at object level.

NOte: If we enable object locking then versionining will be enabled by default.


=================================
What is Transfer Accelaration
=================================

=> It is used to speed up data transfer process in s3 bucket.

=> When we enable Transfer Accelaration it provides endpoint url to upload the data to s3 bucket quickly.

Note: If we enable Transfer Accelaration bill will be generated.


                Janabhoomi express (6 hrs, 300 Rs)
Hyd -----------------------------------------------------------> Vijaywada


                Vande Bharat Express (3 hrs, 1000 Rs)
Hyd -----------------------------------------------------------> Vijaywada


===============
AWS S3 Limits 
===============

=> By default we can create upto 100 s3 buckets per aws account. However we can request AWS support team to increase the limit.

=> Individual object size can be upto 5TB. For uploading large object we can use multipart upload. 
For uploading large object we can use multipart upload

Note: In one bucket we can upload unlimited objects.


=========================
Realtime Usecases of S3
=========================

1) Application files (images, audios, videos, docs...)

2) Database backup files

3) EBS volumes snapshots

4) Server log files


===========
Summary
===========

1) What is AWS S3 & Why ?

2) S3 Buckets & Objects

3) Static website Hosting using S3

4) S3 Storage Classes

5) Versioning

6) Bucket Locking

7) Transfer Accelaration

8) S3 Limits

9) Real-Time usecases