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Remote backup and recovery has traditionally been decentralized for two reasons: the high cost of moving large quantities of data to a centralized location, and slow access time to this data for remote recovery. Bandwidth is costly, and in many remote locations the availability of even sufficient capacity is a stretch. Compounding the problem is the fact that traditional backup is a batch-oriented activity that involves moving lots of data in a limited period of time. The additional bandwidth needed to support that type of activity across a WAN was impossible to justify. There's also the matter of recovery: While backing up over a small pipe is painful, restoring volumes of data can be excruciating.
As a result, firms tended to implement ROBO backup in accordance with a "mini-data center" model, equipping each location with its own backup server and tape drives or small library. Someone at the remote office periodically inserted and removed the tapes and, with luck, tapes were occasionally sent to an offsite location. Quality and consistency of data protection varied dramatically from site to site.
Several technologies have evolved that have led to shifting backup paradigms and new alternatives for remote backup. These range from improving the traditional remote backup model to eliminating the need for remote backup and potentially even remote servers and storage. These include:
Disk. As with backup in general,
Replication. Limited backup operational capability and the need to move data offsite make it reasonable to consider replication as an alternative to remote backup. Moving data back to the corporate data center where it can be managed (and backed up) as part of standard operations makes sense. This requires bandwidth, but unlike the concentrated high-capacity demand of nightly backup, it's a continuous flow based on the change rate of data. Because replication alone presents a challenge when recovering large volumes of data at the remote location, it's typically deployed with other technologies.
This was first published in September 2007