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S3 Object Tags are key-value pairs applied to S3 objects.

Why tags?

Tagging help to create IAM policies, customize storage metrics and setup S3 Lifecycle policies such as transitions between storage classes and expire objects in the background.

Tags can also be used to label objects that belong to a specific project or BU, which could be used in conjunction with lifecycle policies to manage transitions.

Used to upload a single file in multiple parts.

Parts are automatically assembled after all uploads. 

Parts can also be uploaded in parallel, in any order and can even be retransmitted. 

Objects can also be uploaded even before the final size is known (e.g. upload as you are creating it).

It is possible to stop a multi-part upload. Once stopped, it may be aborted or resumed. 

S3 Cross-Origin Resource Sharing (CORS)

Cross-origin resource sharing (CORS) defines a way for client web applications that are loaded in one domain to interact with resources in a different domain. 

Example scenarios:

1. Allow JavaScript on the web pages that are stored in a bucket to be able to make authenticated GET and PUT requests against the same bucket by using the Amazon S3's API endpoint for the bucket.

You can host your entire static website on S3 for an inexpensive, highly available hosting solution that scales automatically to meet traffic demands.

Static content idealy include html files, images, videos, and client-side scripts such as JavaScript. 

You can map your domain name (e.g. “example.com”) to this bucket from Route 53. 

Will list down imporant notes on S3 APIs here.

Common S3 API Calls (Exam Tips)

• DownloadBucket

• CompleteMultipartUpload

• UploadPart

Common S3 response headers (Exam Tips)

• x-amz-delete-marker

• x-amz-id-2

An S3 signed URL includes additional information such as an expiration date and time that gives you more control over access to your content.

The additional information appears in a policy statement, which is based on either a canned policy or a custom policy:

We will discuss some of the policies of S3. Other policies may have a separate page of its own.

S3 Pricing

S3 charges you for following:

1. Data storage (monthly). Is different for different region.

2. Requests to the buckets and objects

3. All data transferred out (e.g. downloads), but no charges for data coming in (e.g. uploads).

S3 Transfer Acceleration enables fast, easy, and secure transfers of files over long distances between your client and your S3 bucket.

Transfer Acceleration leverages Amazon CloudFront’s globally distributed Edge Locations.

As data arrives at an AWS Edge Location, data is routed to your Amazon S3 bucket over an optimized network path. According to an Amazon blog, improvements are typically in the range of 50% to 500% for cross-country transfer of larger objects, but can go ever higher under certain conditions.

Different storage tiers have different cost. S3 Lifecycle management provides the ability to define the lifecycle of your object to transition to different storage tiers based on different factors.

For example, you can set infrequently accessed objects to move into lower cost storage tier (like S3-IA) after a period of time. After another period, it can be moved into Amazon Glacier for archive and compliance, and eventually deleted.

Glacier is a secure, durable, and extremely low-cost cloud storage service for data archiving and long-term backup. Customers can reliably store large or small amounts of data for as little as $0.004 per gigabyte per month.

Glacier Data Retrieval Process

1. To retrieve Amazon S3 data stored in Amazon Glacier, initiate a retrieval request using the Amazon S3 APIs or the Amazon S3 Management Console.