Although Storage Made Easy does not cache any data, if 'resume upload' is enabled for a package files ban be stored on the server whilst uploading (to enable resume to occur) which can fill up the disk space. You can disable this from the package assigned to the users as the appladmin user.
You can also increase the disk space for the appliance by following this article
Temporary files are stored at
in the event you need to clear the files manually prior to applying the suggested changes.