D2D2T is the best, most reliable solution for backup, combining the best attributes of both tape and disk-based backup schemes. The ubiquity and long shelf life of tape can be leveraged, while D2T's poor RTO and RPO can be addressed. Conversely, the expense of additional disk storage and the licensing fees that backup software vendors often charge to support D2D backup schemes can be ameliorated to a degree.

While D2D2T strikes a good balance between D2T and D2D, iSCSI makes D2D2T even better, in two ways: by eliminating the need for a dedicated backup server, and by providing CDP through the use of snapshots. Granularity of backups can be reduced down to the order of minutes, greatly improving the poor RTO and RPO of D2T backups. Backups can be performed in the background by offloading to the iSCSI storage device, so application performance is uninterrupted and not degraded. Topics: Disk-to-Disk Backup Tape Backups iSCSI SAN Storage Management SAN NAS