Disk-to-disk backup or D2D backup is a backup and restore process in which source data is written to and restored from hard disk. Disk-based backup systems can operate locally onsite or offsite via IP-WAN, transferring data to a remote disk
storage facility, also known as televaulting.
Organizations traditionally use disk-to-disk backup for critical data, since hard disk is more reliable and offers faster data backup, and more importantly, quicker restores in the event of data loss.
D2D backup systems were formerly only available to enterprise-class organizations, who opted for expensive disk-based backup and recovery solutions due to their quick recovery times, but in recent years D2D has become significantly more affordable and is now available for SMBs and even home office users. The decreasing cost of hard disk storage makes D2D feasible for more organizations and offers the advantage of rapid recoveries, as well as improved recovery rates compared to tape backup.
Disk-based backup systems offer better
granularity, since storage connected via SCSI or via network attachment can be explored more easily than removable media or backup tape. D2D systems also offer better scalability for a data backup infrastructure than other forms of data storage.