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Amazon EC2 vs Amazon S3: Difference and Use-Cases

If you want to make the most of the AWS cloud, then, Amazon EC2 and Amazon S3 are both important services to understand. This article explains what each service does, how you can use them together and which additional AWS services (such as EFS and EBS) you might wish to use in conjunction with EC2 and S3.

What is Amazon EC2?

Amazon EC2 (which is short for Elastic Cloud Compute) is a service for running servers in the cloud. When Amazon introduced EC2 in 2006, this type of service was a big deal because it allowed companies to spin up servers quickly and easily in the cloud, rather than having to purchase, set up and maintain their own servers on-premise.

Most of the Amazon EC2 server instances are virtual machines hosted on Amazon’s infrastructure, although Amazon Web Services now also offers bare-metal EC2 instances. (Bare-metal cloud instances allow users to host a workload directly on a physical server, instead of a virtual machine. The server is managed by the cloud provider, so users do not have to set up or maintain the hardware.) A wide variety of EC2 instances are available at varying price points; in general, the more computing power you want, the higher the cost of the EC2 instance you need. Some Amazon EC2 instances are tailored for special types of use cases, such as performing parallel processing on GPUs for big data workloads.

In addition to making it fast and easy to set up a server, EC2 offers features such as autoscaling, which (among other benefits) automates the process of increasing or decreasing the compute resources that are available to a given workload. In this way, autoscaling helps to optimize costs and performance, especially for workloads whose scale fluctuates widely.

What is Amazon S3?

Amazon S3 is (as its full name, Simple Storage Service, implies) a storage service that runs on the AWS cloud. It allows users to store almost any type of data in the cloud and manage storage via a Web interface, the AWS Command Line Interface or the AWS API. To use S3, you have to create what Amazon calls a “bucket,” which is a specific object that you use to store and retrieve data. You can set up multiple buckets if you like.

Amazon S3 is an object storage, which works especially well for storing data that is very large in size, irregular in format or highly dynamic. (For more on the benefits of object storage, especially in the context of cloud computing, check out our article about cloud object storage.)

S3 is not the only storage service available on AWS. Amazon Elastic Block Storage (EBS) and Elastic File System (EFS) are two other popular methods of storing data, and are designed especially for use with EC2 (although they are not strictly limited to this type of use case). Compare Amazon S3, EBS and EFS to learn more.

Amazon EC2 vs. Amazon S3: What’s Similar, What’s Different?

The differences between Amazon EC2 and Amazon S3 are easy to understand: The former is a service for accessing cloud-based servers, while the latter is a storage service. They’re different types of things.

That said, EC2 and S3 are closely related services. If you use one, there is a good chance you will use the other. That is particularly true for the following reasons:

  • Amazon EC2 is a popular solution for hosting websites or Web apps in the Amazon cloud. For those use cases, Amazon S3 offers an easy and highly scalable means of hosting the static data that the website or Web app serves.
  • S3 buckets can be used as a storage location for backing up data from inside EC2 instances. (As we explain in the article on how to back up Amazon EC2 instances, this is only one of several possible approaches for backing up EC2.)
  • Because the same S3 storage bucket can be accessed by multiple EC2 instances, as well as various other types services on the AWS cloud, S3 is a useful solution for sharing data between EC2 instances and beyond. (Indeed, you could even access S3 storage from applications that you host on-premise, so it’s a handy way of sharing data between the cloud and your local infrastructure.)

On the other hand, EC2 and S3 don’t go hand-in-hand in all situations. Amazon S3 is not an ideal storage solution for hosting highly dynamic website data, like server-side session data. In addition, while there are several approaches available for backing up S3 data to local storage or to other locations in the cloud, backing up S3 buckets will back up only the data inside those buckets. Therefore, if you want to back up all of the data inside an EC2 instance -- including the data used to create the instance itself -- you need to use additional backup methods. (For an overview of EC2 backup strategies, see this article.)

Conclusion

Amazon EC2 and Amazon S3 are fundamentally different types of services. One allows you to run servers in the cloud with minimal effort on your part, while the other is one of several storage services available from Amazon Web Services. Yet despite these differences, EC2 and S3 complement each other in significant ways, and you’ll often find them being used together.