Event ID 6398 Timer Cache cluster is down, restart the cache cluster and Retry.
Every few minutes my dedicated search server in SharePoint 2013 would complain with an event ID 6396
Unexpected exception in FeedCacheService.IsRepopulationNeeded: Cache cluster is down, restart the cache cluster and Retry.
The cache cluster was up and healthy according to results of Get-CacheHost command
restart-CacheCluster didn't help.
Here's how I solved it:
I cleared the config cache:
- Stop the timer service on all servers in the farm
- Delete all the XML files (Do not delete the cache.ini) in C:\ProgramData\Microsoft\SharePoint\Config\
(NOTE: look for the folder with a current date stamp if there are several GUID folders)
- Edit the cache.ini file and replace the number value to "1"
- Start the timer service on the app server (or first app server if you have many)
- Start the timer service on all the other servers in the farm