AWS Classroom Series – 19/Dec/2020

Eventually Consistent Data

  • S3 replicates data in multiple locations (Az’s), due to this there might be delays while updates to existing objects to propagate across the system. So when we upload a file (which is already existing) there can be a delay of max two seconds. so design your applications accordingly
  • Aws uses Read after write as a consistency model
    • When two users are trying to read data and at the same time if user 3 tries to write data, write will be done first and read access will be given after write to maintain consitency


  • AWS S3 objects can be versioned.
  • S3 objects can be versioned while creating the bucket Preview Preview Preview Preview Preview
  • Upload a new version of a file Preview
  • AWS can enable versioning and suspending versions, bcoz aws will not delete the older version on its own, user has to do it. Preview Preview Preview


  1. Create an S3 bucket with folders
    1. documents
    2. videos
    3. music
  2. Enable versioining after creating the bucket
  3. Uplod readme.txt in documents folder
  4. reupload readme.txt with changed content
  5. verify whether versions are shown by using list versions.


  • Create the folder structure in your local system Preview
  • Now try to create same folder structure in s3 bucket
  • Creating the structure manually is a painfull process if the folder structure is complex
  • Solution: AWS CLI Comes to the rescue, So we need to configure aws cli


  • How to manage access levels so that not every one will be able to access objects in AWS S3
  • Giving access to only few users in your organization to read/write the data

Installing and configuring aws cli

  • Refer Here to install and configure aws cli on windows

Ensure you understand Json Format


  • Ensure you have the following downloaded into your system
    • two audio files
    • two video files
    • ten images

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