For file system reporting, the dates that are allowable are driven by when the result sets where created on the cluster. File System Analytics data is produced by the FSAnalyze job on the cluster. You will only see dates in that drop down that correspond to the actual times that job was able to run to completion on the cluster.  Generate result sets are periodically deleted from the cluster based on a retention policy that can be configured by clicking the Settings tab, clicking the Configure link next to the monitored cluster you want to configure and then clicking on the FSA settings tab and adjusting the retention settings values. The built-in help has more information on how you can do that.
Is there a way to set a longer date range in the File System Reporting section of IIQ?  I have a customer that would like to have larger range.   When I looked in the demo cluster it didn't give me an option to select a range.  Am I missing some setting?
IIQ File System Reporting - report data range