Your general backup strategy should follow something like doing full/incremental and/or snapshot based backups. So in the case of your media, if you do a daily

Your general backup strategy should follow something like doing full/incremental and/or snapshot based backups. So in the case of your media, if you do a daily snapshot then your daily backups would be very small. And if the media doesn't change that often you can keep weekly copies for several weeks, monthly copies for many months, and several years of yearly snapshots. The other strategy is with tape rotation. You need to have about 30x the tape storage as you have online storage, so you can keep 7 yearly backups, 12 monthly, 6 weekly (all full backups), and 7 - 14 daily incremental backups.