Today I came across an issue that arose from a much larger problem I was experiencing. In the Event Viewer I noticed an error I had not seen before referencing the Centralized Logging Agent.
Event ID: 33020
Description: Centralized Logging Service Agent Error while moving cache files to network share.
To my knowledge at this point there has never been a need to consolidate log files to a network share, so I ran the command Get-CsClsConfiguration on both the environment that was experiencing the issue and two other environments that were not. The results were identical in that the cache file network location was not set.
Restarting the Logging service did not resolve the issue for me, so I had to set a network location for these using the following command
Set-CsClsConfiguration –CacheFileNetworkFolder \\dfs.domain.com\shares\skype\logging
Once this was set, the centralized logging service was happy again. Looking at the folders, it creates a sub folder for each Skype for Business server and then moves the log files generated by cls logging from the temp folder to the network share. Not sure why Skype for Business is now adamant it wants this parameter set, but I don’t see the harm in setting it anyway.