SharePoint 2013 Distributed Cache Logon Token issue

​Distributed Cache Service (DCS) is a customized version of Windows App Fabric deployed in SharePoint 2013.

The Distributed Cache service provides caching functionality to features (not to be confused with site features) in SharePoint Server 2013. The Distributed Cache service is either required by or improves performance of the following features:

1. Authentication;
2. Newsfeeds;
3. OneNote client access;
4. Security Trimming; and
5. Page load performance.

For more detailed about managing and deploying DCS, you can visit this TechNet article.

While implementing a SharePoint 2013 farm, I encountered some errors loading newsfeed, and a decrease in the farm performance.

While examining through the ULS logs, I immediately noticed a lot of dozens of DCS errors logged every 60 seconds. The error was:

The Distributed Logon Token Cache stores the security token issued by a Secure Token Service for use by any web server in the server farm. Any web server that receives a request for resources can access the security token from the cache, authenticate the user, and provide access to the resources requested.

Tracing through the logs, I saw that when a user accesses a page, SharePoint attempts to authorize the user to ensure access can be granted. SharePoint stores the user’s token in the user's browser session and in the DistributedCacheLogonTokenCache container. When SharePoint tried to retrieve the token from distributed cache, the connection would time out or a connection would be unavailable and the comparison would fail. Since it couldn't validate the presented token SharePoint had no choice but to log the user out and redirect them to the sign in page.

In general, the problem might cause failures or performance problems of the following:

• Authentication: Users will be forced to authenticate for each Web front end in a load balanced environment;
• Search web parts;
• Social comments;
• Newsfeeds;
• OneNote client access;
• Security Trimming; and
• Page load performance.

After further research, I found out that Out of the box, AppFabric 1.1 contains a bug with garbage collection and this impacts the SharePoint 2013 farm with the March 2013 CU.

Resolution

1. Apply the AppFabric CU 4, or a later CU on all of your servers in the farm;
2. Restart the AppFabric Service on all servers;
3. Restart DCS service on the servers where the service is running; and
4. Perform an IIS reset.