There is an issue using the app insight for IIS with a shared directory (web farm) or a single server where the site data resides on a NAS or a share. The site directory info monitor is always "unknown." This causes all the sites on the server to show as unknown.
Does anyone have a workaround for this? I am assuming it is related to this same error: http://knowledgebase.solarwinds.com/kb/questions/4916/AppInsight+for+SQL%3A+A+database+is+mistakenly+being+reported+as+having+0+bytes+free%2C+triggering+false+alerts.
The WMI method for enumerating the folder and files doesn't work on shared folders. I hope this gets fixed soon, because this is a common way of building web farms.