in SRM, there you can find mostly short period charts on the dashboards, specifically by last 24 hours. Also mostly of those charts are performance related. You can see only "Storage Objects by Capacity Risk" resource on your Storage Home dashboard that is showing how capacity changed by last 7 days. But if you want to see longer period or other kind of chart, you still can use Reports for that. You can see "Executive Storage Summary - Array Capacity" report that is available out of the box report specified by us, or you can create new report and specify your own charts by your own period as you wish.