In working with a client on their multi-server SharePoint 2013 farm, there were some configuration changes that needed to be made to their Distributed Cache cluster / setup. Part of the issue was the Distributed Cache service was enabled on all servers in the farm. Below are tips that we pulled from the Microsoft documentation (emphasis mine):
- The data is not duplicated or copied on other cache hosts in the Distributed Cache cluster. It cannot be configured for High Availability.
- The Distributed Cache should not be enabled on all servers in a SharePoint farm
- Do not run the following services on the same servers running the Distributed Cache service: SQL Server, Project Server, Excel Services, Search Services
- All servers running the Distributed Cache service must match exactly in terms of total memory specifications on all servers in the cache cluster.
- The recommended minimum total physical memory on the server that runs the Distributed Cache service is 8GB (this is different from the cache size).
- If you are using a cache cluster with more than 1 cache host, ensure the memory allocation for the Distributed Cache service’s cache size on each cache host is set to the same value.
- When server resources utilization reaches near 95%, the Distributed Cache will throttle requests. No read or write requests will be allowed until server utilization is reduced to approximately 70%.
- When you add physical memory to the server, the Distributed Cache service does not automatically recalculate the 10% memory allocation, so when you increase the total physical memory on the server, you have to manually increase the Distributed Cache service’s memory allocation.