The term D2D2T defines a backup strategy using a Disk to Disk to Tape architecture. In a D2D2T architecture, data backups stored on disk storage will eventually be sent to tape, for long-term storage (archiving). The combination of Disk to Disk backup with Tape backup creates a solution which takes advantage of the best of both worlds. Disk to disk backup is ideal for short-term storage, while tape backup is the way to go for long-term storage and archiving.

D2D2T methods:

Conventional D2D2T

A D2D2T configuration where the backup to disk is done on conventional, RAID based, disk arrays. As there is no deduplication, the backup sets are then simply duplicated to tapes.

D2D2T on Deduplicated disk

D2D2T backup to a Data Deduplication enabled disk device (a Virtual Tape Library for example). The disk storage requirements are considerably reduced, as most of the backups data is duplicate data. In this particular case, the disk capacity reduction can go as far as 90%.

The addition of tape backup in both cases will make the solution “greener”, as tape is still the best medium when considering energy efficiency.

The best is the second solution, which provides the advantage of using a virtual tape library (VTL). The use of a VTL with data deduplication is much greener than the use of conventional RAID based disk arrays. It needs less capacity, less disks, and less energy consumption. Data deduplication at the disk staging level means that this D2D2T implementation can support more demanding Service Level Agreements. Why? Because more backups can be stored on disk, and take advantage of the disk speed during restore operations.

The entire solution cost is substantially reduced, as you will need less tape storage capacity. Disk to disk backup, combined with tape backup in a D2D2T architecture is an ideal solution, as it combines the disk speed of the short-term storage with the advantages still offered by tape backup for long-term Data Retention.

Other reasons why a D2D2T solution is still the best for storing large amounts of data for long periods of time are the high energy efficiency, and lower floor space costs the tape brings to the table.