Originally posted on Rentsys Recovery Services' blog.
The question "How far away should my primary data center be from my disaster recovery (DR) site?" has plagued DR planners for years. Companies first began seriously examining the role distance plays in DR after 9/11, when the attacks on the Twin Towers caused a large portion of Manhattan to shut down and all the recovery vendor sites filled to capacity.
Unfortunately, there’s no clear-cut answer to this question. Some suggest locating the backup site at least two FEMA-defined regions away, but most people shy away from setting firm guidelines measured in miles.
Instead, the geography should be dictated by the risks related to your organization’s business processes, data and physical location (a business impact analysis should reveal what these risks are). Once you’re aware of the risks you face, you can weigh the benefits and drawbacks of nearby and distant DR sites.
Nearby Disaster Recovery Site
A nearby DR site is beneficial for a variety of reasons. It’s within driving distance, making it easily accessible. If your DR site is nearby and is unaffected by an incident affecting your primary location, you can continue business operations more quickly than if your DR site were hundreds of miles away. In addition, the bandwidth costs are less, and you’re not as likely to experience significant system recovery delays due to latency issues.
However, the benefit of having a DR site within driving distance depends on the locale's risks. If your region is prone to hurricanes, earthquakes or floods, having a DR site in the same region can be risky. For instance, Hurricane Sandy was 1,100 miles in diameter — that’s more than a third of the continental United States. In regional disasters like this, your DR site could be affected by the same event as your primary facility, rendering it useless.
On the other hand, Spokane, WA is a geologically stable area whose biggest threats are wildfire and train derailment. Many businesses in these areas are comfortable with a nearby DR site as long as the site is on a different power grid.