Systems and methods for backing up storage volumes are provided. One system includes a primary side, a secondary side, and a network coupling the primary and secondary sides. The secondary side includes first and second VTS including a cache and storage tape. The first VTS is configured to store a first portion of a group of storage volumes in its cache and migrate the remaining portion to its storage tape. The second VTS is configured to store the remaining portion of the storage volumes in its cache and migrate the first portion to its storage tape. One method includes receiving multiple storage volumes from a primary side, storing the storage volumes in the cache of the first and second VTS, and migrating a portion of the storage volumes from the cache to storage tape in the first VTS.