Patching Distributed Cache in SharePoint Server 2013

The Distributed Cache plays an important role in SharePoint Server 2013 as it’s a key component for performance and caching. Distributed Cache is not a SharePoint service, it’s a standalone service called AppFabric 1.1 for Windows Server. SharePoint Server 2013 requires Windows Server App Fabric and the App Fabric 1.1 CU 1 (KB 2671763) to be installed. It takes care and improves the performance of the following features in SharePoint Server 2013:

• Authentication
• Newsfeeds
• OneNote client access
• Security Trimming
• Page load performance

This document explains in detail about the procedure to be followed for patching the App Fabric component in Windows Server. An App Fabric Cumulative Update is exactly the same as a CU for SharePoint, it contains all previous CUs. So if we install CU6 you also get CU1 to CU5 installed.

List of App Fabric 1.1 Cumulative Updates:

• CU1 – KB2671763
• CU2 – KB2716015
• CU3 – KB2787717
• CU4 – KB2800726
• CU5 – KB2932678
• CU5 – KB2932678
• CU6 – KB3042099

Note:

If you want to identify the version of App Fabric installed in your machine and also the CU version which is installed, please go to the “Programs and Features” section in Control panel and take a look at installed updates.



i. The version number would be listed there.
ii. The installed CU would also be listed there with the corresponding KB number.

System Requirements:

1. Windows Server 2012/2012 R2 32-bit or 64-bit.
   
   
2. Before applying the cumulative update, make sure you have administrative privileges on the computer where you're installing this software.
   
   
3. To apply this cumulative update package, we must have AppFabric 1.1 for Windows Server installed. Additionally, we should also have the Microsoft .NET Framework 4.5 installed.
   
   
4. A system restart is required after installing the Cumulative Update.

Now let’s take a look at the steps to be followed for installing the CU on a server running SharePoint 2013.

Listed below are the steps to be followed for applying the App Fabric CU’s:

1. Please download the CU from Microsoft download center. I’m considering the CU 6 here.
   
   Download App Fabric 1.1. CU 6
   
   
2. Once done downloading the cumulative update package to the server in which you’re going to run it, please run the below mentioned to gracefully shutdown the service instance on the local machine.
   
   Stop-SPDistributedCacheServiceInstance–Graceful
   
   
3. This command will gracefully shutdown the service instance on the local machine. A graceful shutdown means that all the cache items will be distributed to the other service instances in the cache cluster.
   
   
4. Wait for minutes to make sure that all the cached items has properly propagated to the other servers.
   
   
5. Now it’s time to run the package, run the patch executable and follow the instructions. It’s basically a next, next, finish procedure. The App Fabric 1.1 CU 6 doesn’t need any specific change to be made on the DistributedCacheService.exe.config file like how CU 3 did. So please proceed further by clicking next.
   
   
6. Once you’re done installing the CU, please restart the computer.
   
   
7. When the machine is back online, please run the below mentioned command to start the service instance again. The App Fabric Windows Service will be disabled when its shutdown and we are not supposed to start it manually. Please use the below mentioned PowerShell command to do that.
   

   $instanceName ="SPDistributedCacheService Name=AppFabricCachingService"
   $serviceInstance = Get-SPServiceInstance| ? {($_.service.tostring()) -eq $instanceName -and ($_.server.name) -eq $env:computername}
   $serviceInstance.Provision()

8. This command will turn on the Distributed Cache service instance on the machine and will start the AppFabric Windows Service.
   
   
9. Once you’re done completing all the above mentioned steps you’re now ready to move on to the next machine.
   
   
10. Please allow some time for the newly patched cache service instance to catch up.
    
    
11. Finally run the below mentioned commands to check if the Distributed cache service is back online.
    
    To see what Distributed cache-servers SharePoint are, then run this:
    
    Get-SPServiceInstance| ? {($_.service.tostring()) -eq "SPDistributedCacheService Name=AppFabricCachingService"} | select Server, Status
    For AppFabric run this from a machine already in the cache-cluster:
    Use-CacheCluster
    Get-CacheHost
    
    
12. This will confirm whether the Distributed cache service is back online from a SharePoint as well as from an App Fabric perspective.
    
    
13. For any reason, if you don’t see the status of the servers as “online”, please go ahead and run the below mentioned command to remove and re-add the Distributed Cache Service Instance.
    
    To remove: Remove-SPDistributedCacheServiceInstance
    To Add : Add-SPDistributedCacheServiceInstance
    
    
14. Run the remove command first and then wait for couple of minutes and then run the add command.
    
    
15. At last, once everything looks fine you’re good to go ahead and patch the second server following the same steps mentioned above. 

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