This issue is typically seen after an upgrade to 6.7.x.x branch of SGOS. This is a minor issue, but fills up the Event Log with messages.
These are the core issues that will be reported, a list of categories will follow after the word "category:".
CFS error: Failed to create PDM trend group cfs:IWF:
CFS error: Failed to create PDM trend group cfs:Optenet:category:
CFS error: Failed to create PDM trend group cfs:Proventia:category:
CFS error: Failed to create PDM trend group cfs:YouTube:category:
CFS error: Failed to create PDM trend group cfs:Blue Coat:category:
SGOS 6.7.x.x
Issue occurs after upgrade of SGOS to 6.7.x.x.
ProxySG Management Console > Maintenance > Systems and Disks > Tasks > Click on "Clear the Trend Statistics"