Today I wanted to talk about Distributed Cache (or also called AppFabrikCache) on SharePoint Server 2013.

This new way of caching was originally based on the “Cloud” of Microsoft (Azure) but has been integrated on the On Premise systems of Microsoft. The Distributed Cache can be deployed on 2 different ways

• Dedicated Mode
• Collocated Mode

On the dedicated mode only this service is running on the application server and all other services are stopped who is hosting the AppFabric Cache Service.

On The Collocated mode the Distributed Cache is running with all other Service Applications on the Application Server. This is the recommended mode for deploying Distributed Cache.

The SharePoint Prerequisites installation Wizard installs The AppFabric Cache who is needed for SharePoint 2013. Without this prerequisites you can’t install or run SharePoint 2013. How do we configure it or how do we use this cache? Actually you have to do nothing, it’s all made automatic. In a SharePoint Server 2013 farm, there must be at least one cache host running the Distributed Cache service.

What do we find on this cache?

• Microblog activities
• Following activities
• User profile activities
• Document activities
• Claims, Security…
• Token

Check the following link to get a better overview of it: http://technet.microsoft.com/en-us/library/jj219700.aspx

Benefits of using the microblog features, feeds, and the Distributed Cache

Some benefits of using microblog features, feeds, and the Distributed Cache include the following:

• Allows users to stay in touch with individuals and specific groups of people over time and distance.
• Allows users to stay informed about what’s going in the organization.
• The focus of the interactions is around people or teams, and not so much the topic being discussed.
• It is difficult to keep track of activities related to documents, discussions, and lists in SharePoint without manually visiting the item regularly. Feeds collect and deliver information to users that they would otherwise have to spend time searching for.
• The feed gives users a single place where they can stay up-to-date with all of the content and people they work with.
• Allows quick conversations to take place.

Distributed Cache

For SharePoint Server 2013 you have to plan the capacity of Distributed Cache. It’s not because it’s installed automatically that you don’t have to plan it…

As you know the AppFabric Cache stocks data on memory and uses when users try to access it. So if you have more than 500.000 users you need 12GB cache size of the Distributed Cache service. So if you give him only 1 GB, you will ensure some problems.

Distributed Cache 2

How is the memory allocated to the Distributed Service?

By Default it takes 5% of the physical memory of the server. You can’t change this on the Central Administration by the UI but only by PowerShell: Update-SPDistributedCacheSize. This PowerShell command Specifies the memory size in megabytes (MB) that you want to allocate to the Distributed Cache service. The default value is 5 percent of total system random access memory (RAM). This value should not be more than 40 percent of total system RAM with a maximum limit of 16 gigabytes (GB).

More information about the PowerShell Command: http://technet.microsoft.com/en-us/library/jj730453.aspx

An example of changing the SPDistributedCacheSize

Distributed Cache 3

Important to know is that if you are using a Virtual Machine and not a Physical Machine for your SharePoint Farm(s) do not use Dynamic Memory Usage. The Memory Allocation for Virtual Machines should be on “Fixed” Memory.

When the Distributed Cache service runs in collocated mode, the physical memory of the server should be increased and all non-essential services stopped. It is not recommend that any of the following services or applications run on the same server as the Distributed Cache service:

• SQL Server 2008 or SQL Server 2012
• Search service
• Excel Services in SharePoint
• Project Server services

Firewall configuration considerations

The Distributed Cache service uses the following communication ports:

• 22233 (CachePort)
• 22234 (ClusterPort)
• 22235 (ArbitrationPort)
• 22236 (ReplicationPort)