Backups of computer data are needed more today than ever before. In addition to common human error, our data is exposed to environmental hazards, equipment failure, and malicious attacks. The idea that disk mirroring within RAID technology is sufficient by itself to secure data is not well founded in the reality of information systems.
Many believe and most rightfully so, that the advantage of RAID is that fault tolerant and redundant backup schemes exist within the technology to help prevent or predict failure, or at the very least, offer an economical way to recover as much (potentially lost) data as possible. Unfortunately, RAID technology without an optimized backup and recovery strategy (across the enterprise) can leave a company without data when it’s needed, a longer than desired recovery time objective, or worse, irretrievable data loss. The primary reason this is evident is because technology is not perfect, it will eventually fail; the architecture is not perfect and system design compromises are often necessary to control costs or access constraints.
Disk mirroring is a very commonly found version of RAID technology often called RAID-1. It costs 2-3 times single disk striping (RAID =0), has higher reliability than all but RAID-6, and has higher transfer rates and maximum I/O rates than single disk. RAID-1 It has become the data backup scheme of choice for many a business.
In another life, I was the lead reliability engineer on early versions (some say the first) of a RAID-6 subsystem technology, a product known as Iceberg. The RAID-6 claim to fame is that it is the highest reliable RAID technology. And, even with such promises of high availability, additional backup and recovery schemes were (and are) necessary. RAID represents the technology including hardware, software, peripheral devices and the mechanisms to connect to the user community. However, a proper backup and recovery strategy considers the failure mechanisms, disaster impacts, downtime precipitators, and human factors that will inevitably interrupt the backup system.