• Disk-to-disk backup uses same basic architectures and same backup applications
• Uses low-cost SATA disk storage along with tape
– Backup to SATA disk for fast recovery – Also backup to tape for archival purposes
LAN
Master backup server
Application Servers with
Backup client
SAN
Low-cost disk storage
Tape storage is no longer the only cost-effective backup method. In recent years, the cost of a disk backup solutions using SATA drives can actually be lower than that of a comparable tape implementation. SATA disks can be as cheap as (or cheaper then tape), when the cost of the enclosures and of media management are factored in. Physical tape media are generally considered unreliable and are often a source of backup failures. Tapes cannot offer the longer life cycles provided by disk drives. Newer SATA drives not only have a relatively high Mean Time Between Failure (MTBF), but when combined with RAID, multiple layers of data protection are provided. With the decreasing cost of disk, disk-based backup is feasible and offers the advantage of much more rapid restore. However, the need to retain more and more information for longer periods of time means that a pure disk solution is impractical. Most companies also need archival storage, so disk-to-disk backups are usually used in conjunction with standard disk-to-tape backups. Some vendors now offer disk-to-disk-to-tape solutions that automate the entire process.