Disaster recovery

Disaster recovery is the process, policies and procedures of restoring operations critical to the resumption of business, including regaining access to data (records, hardware, software, etc.), communications (incoming, outgoing, toll-free, fax, etc.), workspace, and other business processes after a natural or human-induced disaster.

Prior to selecting a Disaster Recovery strategy, the Disaster Recovery planner should refer to their organization's business continuity plan which should indicate the key metrics of Recovery Point Objective (RPO) and Recovery Time Objective (RTO) for various business processes (such as the process to run payroll, generate an order, etc). The metrics specified for the business processes must then be mapped to the underlying IT systems and infrastructure that support those processes.

Once the RTO and RPO metrics have been mapped to IT infrastructure, the DR planner can determine the most suitable recovery strategy for each system. An important note here however is that the business ultimately sets the IT budget and therefore the RTO and RPO metrics need to fit with the available budget. While most business unit heads would like zero data loss and zero time loss, the cost associated with that level of protection may make the desired high availability solutions impractical.

The following is a list of the most common strategies for data protection.

• Backups made to tape and sent off-site at regular intervals (preferably daily)
• Backups made to disk on-site and automatically copied to off-site disk, or made directly to off-site disk
• Replication of data to an off-site location, which overcomes the need to restore the data (only the systems then need to be restored or synced). This generally makes use of Storage Area Network (SAN) technology
• High availability systems which keep both the data and system replicated off-site, enabling continuous access to systems and data

In many cases, an organization may elect to use an outsourced disaster recovery provider to provide a stand-by site and systems rather than using their own remote facilities.
In addition to preparing for the need to recover systems, organizations must also implement precautionary measures with an objective of preventing a disaster situation in the first place. These may include some of the following:

• Local mirrors of systems and/or data and use of disk protection technology such as RAID
  Surge Protectors — to minimize the effect of power surges on delicate electronic equipment Uninterruptible Power Supply (UPS) and/or Backup Generator to keep systems going in the event of a power failure
• Fire Preventions — more alarms, accessible fire extinguishers
• Anti-virus software and other security measures