Introduction to Windows Azure AppFabric blog posts series – Part 3: The Middleware Services Continued - Windows Azure AppFabric Team Blog - Site Home - MSDN Blogs

Introduction to Windows Azure AppFabric blog posts series – Part 3: The Middleware Services Continued

Introduction to Windows Azure AppFabric blog posts series – Part 3: The Middleware Services Continued

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In the first post we discussed the 3 main concepts that make up Windows Azure AppFabric: Middleware Services, Building Composite Applications, and Scale-out Application Infrastructure.

In the second post we started discussing the Middleware Services that already available in production: Service Bus and Access Control service.

Focus on Caching

In this post we will discuss the Caching service. The Composite App service will be discussed in the next post as part of Building Composite Applications, and the Integration service will be discussed in a future post as well.

As noted in the previous post, the Caching service is available as a Community Technology Preview (CTP), and the Integration and Composite App services will also be released in CTPs later in 2011.


The Caching service is a distributed, in-memory, application cache that can be used to accelerate the performance of Windows Azure and SQL Azure applications. It provides applications with high-speed access and scalability to application data.

For instance, if you are developing a web application, you would use the Caching service in order to store frequently accessed data in-memory closer to the application, so you don't have to pay the penalty of fetching the data from the data store. Examples for such data would be a list of countries, or a static image that is part of your webpage.

Another very useful usage scenario of the Caching service is for ASP.NET session state data. Session state is data that is kept during a user's specific session with your website. An example for such data is a customer's shopping cart information. It would be useful to keep this data in-memory until the customer confirms the purchase. The ASP.NET application can be configured to use the Caching service to store the session state data in a cache without having to change a single line of code, you are only required to make a few minor changes in the configuration file.

When running a web application using Windows Azure Web Roles, a single user might be catered by different Web Roles as result of load balancing activities or in case one of the Web Roles stops working. The fact that the user's session data is kept in a central cache makes the user's data always available and enables you to provide a consistent experience and high-availability to the data in such cases.

Another great feature of AppFabric Caching is the "Local Cache". When using this feature you can also keep cached data in the available memory in your web or worker roles, in addition to the central cache. This way the cached data is even closer to your application.

The image below illustrates how the Caching service keeps data in-memory closer to the application and accelerates the application's performance by saving the need to fetch data every time from the data store:

The Caching service delivers all these great capabilities while providing inherent elastic scale, low latency, and high throughput. In addition, it is very easy to provision, configure and administer.

As noted earlier, the Caching service is already available for you to explore for free as a CTP in our Labs/Preview environment. We recently released an update to the service that added more cache size options, and the ability to dynamically change the cache size. More details can be found here.

The service will be released as a production service with full SLA in a few months.

This service is based on the Windows Server AppFabric Caching technology, which is a proven, on-premises technology available on top of Windows Server. If you are already using the on-premises version of the cache as part of your application, you should be able to use the Caching service in Azure AppFabric with only minor changes to your application code, if at all. Most importantly, as in all other Windows Azure AppFabric services, in the cloud you don't have to install, update, and manage the service; all you need to do is provision, configure, and use. You should note that there are some on-premises features in Windows Server AppFabric Caching that are not available in Windows Azure AppFabric Caching, but we will gradually add these features in each release of the service. For more information, see the Caching Programming Guide on MSDN.

Using the same technology both on-premises and in the cloud is one of the basic promises in AppFabric that addresses the challenges faced by developers discussed in the first post.  More on this will come in future posts...

For a more in-depth and technical overview of the Caching service, please use the following resources:

Basically, any content related to how to use Windows Server AppFabric Caching will be relevant as well, except for content on how to install, configure, or manage, which are already taken care of by the platform.

As you can see from this post, the Caching service, like the Service Bus and Access Control services, makes the developer's life a lot easier by providing an out-of-the-box solution to complicated problems that developers are faced with when building applications.


As a reminder, you can start using our CTP services in our LABS/Preview environment at: Just sign up and get started.

Other places to learn more on Windows Azure AppFabric are:

Be sure to start enjoying the benefits of Windows Azure AppFabric with our free trial offer. Just click on the image below and start using it already today!

Finally, please leave your comments and questions in the comments section below.

Itai Raz, Product Manager


  • It sure would be great to hear pricing and size options.

  • We will release all these details with the release of the service.

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