AWS S3 – Simple Storage Service

Simple, durable, massively scalable object storage

S3 is one of the most amazing features of AWS and heavily featured exam topic in AWS certifications.

You have to know what are the different storage types, classes available in S3. Which is ideal for the given scenario, how to move the data in and out of the S3 etc.

Below are the general overview and exam tips for the S3.

  • S3 is an object storage service. You can store flat files, host a static website but can’t install operating systems or run a dynamic site.
  • It’s a highly available and durable service. The data stored is backed up in multiple availability zones by default and cost effective as well.
  • There are three types of S3 storage classes available. S3 – Standard, Infrequent access, Glacier.
  • Remember, Reduced Redundancy Storage (RRS) is an Amazon S3 storage option.
  • S3 supports SSL encryption of data in transit and at rest. Read about encryption here: S3 Encryption



Individual Amazon S3 objects can range in size from a minimum of 0 bytes to a maximum of 5 terabytes.

The largest object that can be uploaded in a single PUT is 5 gigabytes. For objects larger than 100 megabytes, customers should consider using the Multipart Upload capability.

In short, You can store an object of maximum size 5TB which can be uploaded in chunks.

Maximum size of single chunk is 5GB. You can use multipart upload for faster uploading of chunks size greater than 100MB.

Note: It’s recommended to use multipart upload for objects greater than 100MB size and it’s required to use multipart for files of size 5GB.

Amazon S3 buckets in all Regions provide read-after-write consistency for PUTS of new objects and eventual consistency for overwrite PUTS and DELETES.

If an object uploaded is not immediately reflecting in the bucket, then it means that bucket in the region is using eventual consistency.

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