A storage server creates a first mirror of a primary volume of data on a first storage set that includes at least one disk and creates a second mirror of the primary volume, on a second storage set that also includes at least one disk. The server then quiesces the second storage set. A user then decouples the second storage set from the server and transports the second storage set off-site. The storage server then saves one or more incremental backups of the primary volume on the first storage set according to a specified backup schedule. According to a specified rotation schedule, a user subsequently recouples the second storage set to the server. The server detects the recoupling and, in response, automatically resynchronizes the second mirror with the primary volume, and swaps the active-inactive statuses of the first and second mirrors. The process repeats as needed.