Best practices for offsite storage

The question of distance between production and backup data, regardless of the media, is one that comes back frequently. There is not a lot of "best practices" information available on the subject mostly because the distance requirements will vary based on the region and the specific threats associated with a particular geography. There might be some industry specific guidelines to assist with the decision (the banking industry comes to mind) but no standard or minimum distance has been established. There is typically much more documentation about "how" tapes are stored rather than how far.

There are obvious bad choices such as keeping backup media on a different floor of the same building or even in a neighboring building. That said, it might be acceptable in a particular area to have backup tapes stored in a vault a few city blocks away from the data center. In other areas, such as hurricane-prone regions, the tapes must be kept at a distance greater than the destructive reach of the weather phenomenon.

The bottom line is that backup tapes should be kept at a safe distance from the disruptive or destructive elements that may cause you to need those tapes. Best practices would dictate that a risk assessment be conducted to identify the threats, probabilities and impact. This information can then be used to establish the appropriate distance between production and backup data.