A Crash Course in Amazon Terminology (Part 1)

If you would like to read the next part in this article series please go to A Crash Course in Amazon Terminology (Part 2).


One of the things that tends to confuse those who are new to the Amazon Web Services is some of the terminology that Amazon uses. Like so many other providers, Amazon likes to use a lot of acronyms, and if you don’t know the differences in these acronyms they can be confusing. At the risk of making myself look bad, let me give you an example of what I mean.

I first heard about Amazon Web Services at an IT event a few years back. The speaker kept referring to Amazon Web Services as AWS. That seemed simple enough. AWS stands for Amazon Web Services. A couple of days later however, I attended a session in which a different speaker kept referring to Amazon Web Services as S3. After the presentation I asked the speaker what S3 was, and he replied that he was referring to Amazon Web Services. At that point I knew that there had to be a reason why two different terms were being used, but neither of the presenters really articulated what that reason was. Since this Web site is still relatively new, I wanted to make sure that one of the first articles that I wrote clarified the difference between some of the acronyms that Amazon uses, so that perhaps I could help others to avoid the confusion that I had experienced.

So with that said, you may be wondering what the difference is between AWS and S3. Well, AWS as I previously mentioned refers to Amazon Web Services. Amazon Web Services is a somewhat generic, catch all name for Amazon’s cloud offerings. As the name implies, the Amazon Web Services are made up of various services, each of which has its own name. S3 is one of the many services that make up the larger Amazon Web Services. Incidentally, S3 is a storage service. I will talk more about S3 in a moment. Before I do, I need to talk a little bit more about Amazon’s approach to storage.


The first thing that you need to know about storage is that S3 is not Amazon’s only storage related offering. As I said earlier, AWS is built out of a large number of components and services. In fitting with this model, there are a few different storage services. Each of these services has the ability to store data on AWS, but the storage services differ from one another in terms of cost, capability, and intended purpose. It is also worth noting that there can be differences in cost and capability even within an individual service. I will show you an example of that a little bit later on.

The first storage service that I want to talk about is Amazon Glacier. With pricing starting at a penny per gigabyte, Amazon Glacier is designed to be inexpensive. However, Glacier is not suitable for use as primary storage. It is designed instead for use as long term, archival storage.

Of course this raises the question of what would prevent an organization from using Glacier for a purpose other than archival storage. There are two things – performance and cost. Like most archival storage mediums, Glacier is anything but high performance. The name “Glacier” is a hint as to the level of performance that can be expected.

Cost is the other limiting factor. Yes, storage is billed at a penny per gigabyte of storage, but Amazon also bills customers for uploads and for retrievals. According to Amazon’s Web site, “Glacier is designed with the expectation that retrievals are infrequent and unusual, and data will be stored for extended periods of time. You can retrieve up to 5% of your average monthly storage (pro-rated daily) for free each month. If you choose to retrieve more than this amount of data in a month, you are charged a retrieval fee starting at $0.01 per gigabyte. In addition, there is a pro-rated charge of $0.03 per gigabyte for items deleted prior to 90 days.”

In other words, Glacier storage is specifically designed to become cost prohibitive in the event that an organization attempts to store highly transactional data, or even frequently read data. Glacier is most cost effective when it is used as an archival medium. You can access the full pricing details for Glacier storage here.

Another Amazon AWS storage service is Amazon Elastic Block Store (Amazon EBS). As the name implies, Amazon EBS is block level storage. Amazon intends this to be used in conjunction with Amazon EC2 instances.

I haven’t had a chance to talk about Amazon EC2 yet, but EC2 is Amazon’s server virtualization platform. Virtual machines running on Amazon EC2 are referred to as instances. Amazon EBS allows instance data to be stored separately from the instance. That way, the data will still exist even if the instance is terminated. Furthermore, Amazon EBS is designed to provide low latency, high performance storage that will meet the needs of most virtual machine instances.

Pricing for Amazon EBS starts at five cents per month for each gigabyte of storage and five cents per month for each million I/O requests. Remember earlier when I said that pricing can vary considerably even within an individual service? Well, Amazon EBS is a great example of that. The storage medium has a major impact on the price. Amazon charges one rate for magnetic storage and another rate for SSD storage. You can see the full pricing details here.

So now that I have talked a bit about Amazon Glacier and Amazon EBS, I want to talk about Amazon S3. S3 stands for Simple Storage Service. S3 is Amazon’s most versatile storage. Amazon S3 is based on object storage and is commonly used for things like backups, archiving, and Web content distribution. The S3 storage has built-in redundancy with content spread across multiple datacenters and Amazon guarantees four nines of availability.

Those who sign up for Amazon AWS can get 5 GB of free S3 storage, which includes 20,000 Get requests, 2000 Put requests, and 15 GB of data transfers each month.

Beyond the free 5 GB of storage, Amazon uses a sliding scale for S3 storage pricing. The first TB of storage is priced at three cents per gigabyte per month. The cost per gigabyte decreases as the volume of data increases. Organizations that store over 5000 TB pay 2.75 GB per month. Of course this does not include costs that are associated with storage I/O. Amazon doesn’t charge a fee for transferring data into Amazon S3, but they do charge for data that is transferred out of S3, just as they also charge for routine storage I/O. You can read the full pricing scheme for Amazon S3 storage here.


In this article, I have discussed some of Amazon’s more popular AWS storage offerings. As you read through this article, you might have noticed that my storage discussion never mentioned databases. The reason for this is that Amazon differentiates between database services and storage services. I will be discussing some of Amazon’s database service offerings in Part 2 of this article series.

If you would like to read the next part in this article series please go to A Crash Course in Amazon Terminology (Part 2).

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