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AWS S3 (Simple Storage Service)
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-> 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).

-> We can upload & download objects (files) at any point of time using S3

		One Object = One file

-> In S3, we need to create buckets to store data

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).

-> We can create multiple buckets in s3.

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Static Website Hosting using S3
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-> 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.


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.


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

=> 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 Instance 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)


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Versioning
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=> 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.

Note: Once we enable versioning, we can't disable that but we can suspend it.


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Object Locking
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-> 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.

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What is Transfer Accelaration
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=> 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.



						    janmabhoomi (6 hours) -> 300 RS
			Hyd ------------------------------------------> Vijaywada


								Vande bharat (3 hours) -> 1200 RS
			Hyd ------------------------------------------> Vijaywada


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AWS S3 Limits	
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=> 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.

Note: In one bucket we can upload unlimited objects.


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Realtime Usecases of S3
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1) Application files (images,audios, videos, docs...)

2) DB backup files

3) EBS Volume Snapshots

4) Server Log files


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Summary
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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