start with this page...
http://www.ptc.com/appserver/wcms/standards/support_resource_page.jsp?&im_dbkey=90970&icg_dbkey=917
Look esp. at this document (or equiv for your release - Aphelion is for an older release) http://www.ptc.com/WCMS/files/123335/en/BackupRecoveryTechBrief_x20.pdf