Information Technology (IT) professionals have recognized the importance of disaster recovery for decades. High-profile Internet worms, natural disasters, and other high-profile security breaches all serve as reminders of the need to plan properly for disaster recovery and other business continuity issues.
Disaster recovery applies mainly to corporations and other large organizations, but the same basic principles apply in home networking, too.
What is Disaster Recovery?
Disaster recovery involves a series of actions to be taken in the event of major unplanned outages to minimize their adverse effects. In networking, disasters can result from events such as
- computer malware
- electric power failures
- hacker attacks
- underground cable cuts or failures
- fire, flood, earthquake, and other natural disasters at a facility
- mistakes in system administration
The related concept of business continuity involves insuring that an organization’s critical business processes, including those utilizing IT systems, can be maintained in the event of a disaster.
Why Disaster Recovery is Important
When executed well, disaster recovery procedures save large sums of money. The financial impact to corporations of even a few hours of lost network and Internet connectivity runs easily into the millions of dollars. Disaster recovery can also improve the quality of human life, and it may even save lives.
Loss of cell phone contact with friends and family becomes extremely disruptive during emergencies.
All that said, investments in business continuity need to be balanced against practical considerations of the costs and the complexity of preparing for an unknown future:
- cost – comprehensive disaster recovery is prohibitively expensive
- testability – disaster recovery plans that look great on paper but are technically unproven will mostly likely fail in practice
- overemphasis on the backoffice – it’s easy to get enamored with solutions for the server room, but without adequate provisions for people and the client-side infrastructure, business continuity won’t happen
Home networks lack the expensive hardware of a large business, but the preservation of data and communications can be equally important.
Disaster Recovery Planning
The best approach to disaster recovery focuses primarily on planning and prevention. While earthquakes and terror attacks generally are difficult to anticipate, many other disaster scenarios can be analyzed in detail.
For those events that can’t be prevented, an IT disaster recovery plan takes into account the need to
- detect the outages or other disaster effects as quickly as possible
- notify any affected parties so that they can take action
- isolate the affected systems so that damage cannot spread
- repair the critical affected systems so that operations can be resumed
These are collectively called risk management or risk mitigation activities.
Disaster Recovery Techniques
All good IT disaster recovery plans consider the three main components of operations: data, systems and people.
From the technical perspective, most organizations rely on some form of redundancy to make possible the recovery of data and systems. Redundancy allows secondary data or system resources to be pressed into service on short notice should primary resources fail or otherwise become unavailable. Organizations can replicate servers and other critical hardware at multiple locations to guard against any single point of failure.
While traditional disk mirroring keeps data highly available in normal situations, it works only over short distances. Backups allow snapshots of the data to be captured in moved to remote locations.
Traditional network backup strategies, for example, archive copies of critical data periodically so that they can be restored later if needed. If backups are kept onsite or at only location, their value for disaster recovery is low. Larger organizations invest in storage area network (SAN) technology to distribute data more widely across their internal networks. Some also utilize third-party hosting services for cloud storage.
Home networks can take advantage of network backup and cloud storage solutions as well, to better manage their risks.
Other common techniques for supporting disaster recovery plans include:
- assigning people in the organization with special roles to be done in the event of a disaster, and providing them the necessary training
- performing disaster recovery drills that practice against for specific recovery scenarios