Over the past 40 years of computing, the standard way of protecting primary disk storage data was to backup that data onto one or more magnetic tapes on a daily basis. Magnetic tape will continue to play a critical role in data protection, offering the lowest cost storage medium for maintaining offsite backup data and long term archive data.

But in the last few years, the rapidly falling cost of SATA magnetic disk technology has come closer to the cost of magnetic tape, making it a viable option for specific data protection applications like local data center backup. While SATA is at the core of disk-based data protection systems, there are many system-level implementations, each with its own strengths and weaknesses. This paper will review these systems, which include:

• RAID Disk Backup
• Virtual Tape Libraries (VTL)
• Intelligent Disk-based Data Protection