Introduction to Simple Storage Service

• It is one of the main building blocks of AWS.
• It’s advertized as “infinitely scaling” storage.
• Many website use Amazon S3 as a backbone.
• Many AWS service use AWS S3 as an integration as well.
  

- Usecase:
  - Backup & Storage
  - Disaster Recovery
  - Archival
  - Hybrid cloud storage
  - Application Hosting
  - Media Hosting
  - Datalake and Big data analysis
  - Software delivery
  - Static Website Hosting

S3 Object

• Object contain your data.
• They are like files.
• an object must consists of:

Property	Information
Key	This is the name of the object.
	It is the full path.
	Key is composed of prefix + Object Name:
	E.g. s3://mybucket/my_file.txt
	E.g. s3://mybucket/myfolder/anotherfolder/myfile.txt
Value	MAX OBJECT SIZE: 5TB
	Object values are the contents of the body, it is just stored as a sequence of bytes
	If upload more than 5GB, must use “must-part” upload
VersionId	When versioning is available, its the version identifier.
MetaData	Additional information attached to object.
	It is the list of test key-value pairs
	2 types of metadata: System or User Metadata
Tags	Unicode key-value pair, upto 10
	Useful security/lifecycle

S3 Bucket

• S3 allows people to store files/objects in “buckets” (directories)
• Buckets must have a Globally Unique Name.
• Buckets are defined at a regional level.
• S3 look’s like a global service, BUT, buckets are created in a region.

Naming Convension for bucket
- No Uppercase (A-Z)
- No Underscores(-)
- 3 to 63 characters long
- Not an IP
- Must start with lowercase letter or numbers
- Must not start with prefix (xn—)
- Must not end with suffix (-s3alias)

S3 Security

• User Based:

AWS S3 has IAM Policies:
Which API should be allowed for a specific user from API

• Resource Based:

- Bucket Policies: 
  These are bucket wide rules from the S3 console.
- Object Acces Control List (ACL): 
  Finer grain control (can be disabled).
- Bucket Access Control List (ACL): 
  Less Common (can be disabled).

Note: An IAM Principal can access an S3 object if the user permission allows it or the resource policy allows its & there is no explicit deny.

• Encryption: Encrypt objects in S3 using Encryption Keys.

S3 Website Hosting

• S3 can host static websites and have them accessible on the internet.
• The website URL will be (dependent on region).
• If you get a 403 error make sure the bucket policy allows public read.
• Note: If you want to host a website, every file related to it should be publicly accessible.

S3 Versioning

• You can version your files in Amazon S3.
• It is enabled at bucket level.
• Files before versioning is enabled will have NULL as their version.
• Different versions of some files will still be available even after versioning is disabled afterwards.

Amazon S3 Replication [Cross Region Replication(CRR) & Same Region Replication (SRR)]

• To use this feature, versioning needs to be enabled.
• Bucket can be in different AWS accounts.
• Copying is Asynchronous
• To copy successfully, it must have proper read & write (to S3) permission in IAM.
• Usecase:
  • CRR - Complicance, Low Latency Access, Replication Across Accounts.
  • SRR - Log Aggregation, Live replication PROD & TEST Accounts.

S3 Storage Access

There are 5 types of storage access provided by S3.

S3 Standard (General Purpose)

• 99.99% Availablity
• Used for frequently available data.
• Low latency & High Throughput.
• Can Sustain 2 concurrent facility failures.
• Usecase: Big Data Analytics, Mobile & Gaming Application, Content Distribution, …

S3 Infrequent Access

• 99.9% Availablity
• Lower cost (of retrival) than S3 standard
• For data that is less frequently accessed but require rapid access when needed.
• Usecase: Disaster Recovery, Backups
• A special Case:

  # Amazon S3 OneZone Infrequent Access
  - High Durablity 99.99999999999% (11 9s Durablity) in a 
  single AZ.
  - Data Loss when AZ is destroyed.

S3 Glacier Storage

• Low cost object storage meant for archiving & backup.
• Pricing: Price for storage, object retrival cost.

  - Amazon S3 Glacier Instant Retrival:
    - Amazon S3 Glacier Instant Retrival:
      - Milliseconds retrival, 
        great for data access once in a quarter.
      - Minimum storage duration of 90 days.
    - Amazon S3 Flexible Retrival:
      - Minimum storage duration = 90 days
      - Expedite (1-5 mins)
      - Standard (3-5 hours)
      - bulk (5-12 hours)

S3 Glacier Deep Archive (For LongTerm Storage)

• standard: 12 hours retrival delay
• bulk: 48 hours retrival delay
• Minimum storage duration = 180 days.

Amazon S3 Intelligent Tiering

• small monthly monitoring fees.
• Moves object automatically between Access Tiers
• There is no retrival charges.

Amazon S3 Encryption

There are 2 type of encryptions, Client Side Encryptions of which user is responsible, and server side encryption (which is default mode in the cloud.)

Shared Responsiblity for Amazon S3