Active storage is for data that will be regularly viewed, updated, or accessed. Archival storage is for rarely accessed data. Backup-only storage consists simply of automatic backup of data on a set schedule.
Consult the Sensitive Data Guide to see which data types are permitted for each option.
Backups (or 'snapshots') protect against corruption or unintended user deletion by making scheduled copies of the data. (Note: These automated backups as a service feature are different from manual backups that you may undertake on your own.)
Replication, which is usually required of mission critical systems that must minimize downtime, provides a hedge against equipment failure by creating a copy of data on a separate system. Replication cannot be used to restore deleted data.
All U-M institutional data must be backed up. See Back Up U-M Data for details.