Understanding Disaster Recovery
A Backup Article Contributed by Sharvan Sood
What is Disaster Recovery?
An unforeseen disaster can result in difficult recovery problems -- leading to outages that range from hours to days or weeks. This can cost millions in lost revenue, lost productivity and legal concern to an IT focused organization. In worst case, a prolonged outage can endanger the capability of an organization to carry out its business.
Anticipating these events and planning corrective courses of action to return the entity to an acceptable condition is Disaster Recovery i.e. the ability to respond to an interruption in services by implementing a disaster recovery plan to reinstate an organization's critical business functions.
Disaster Recovery Framework
Critical functions: Business activities or information that could not be interrupted or unavailable for several business days without significantly jeopardizing operation of the organization.
Critical Infrastructure: Systems whose failure would have a devastating impact on the economic security of an organization. For these systems, disaster recovery planning is intrinsic to design.
Critical Records: Records or documents that, if damaged or destroyed, would cause considerable inconvenience and/or require replacement or recreation at considerable expense. For such elements disaster recovery planning should be in the form of contingency plans.
Mission-Critical Application: An application that is essential to the organization's ability to perform necessary business functions.
Basis of disaster recovery is distinguishing the critical functions of an organization and correlating them to the equipment, people, and other requirement that will be needed to run a particular operation. This exercise identifies the financial, operational, and service impacts that may result from a disruption in daily business or organization's operations and aids in proper deployment of IT resources to ensure ongoing availability of mission-critical data.
Two key metrics that helps in establishing an IT facility's capability to manage recovery of data after a disaster:
Disaster Recovery Metric: Rto
Recovery Time Objective (RTO) - The interval of time within which systems, applications, or functions must be recovered after a known outage. For example, if RTO for recover data set from the failed system crash is set as 2 hrs. , then the facility's disaster recovery infrastructure must be configured to honour that obligation.
Disaster Recovery Metric: Rpo
Recovery Point Objective (RPO) - The point in time to which systems and data must be recovered after an outage. For example disaster recovery for Database corruption would be from the last full backup, which could be from the previous week. RPO acts as a determinant of the amount of data that may need to be recreated after the systems or functions have been recovered.
Disaster Recovery Planning
It will be necessary to establish different RTOs & RPOs for each data type within the organization. The lesser an application's RPO and RTO values are, the greater is the organization's reliance on that particular process, and accordingly the higher the priority when arranging recovery of the systems after a disaster. Thus RPO and RTO provide decision makers the necessary information they need to identify an apposite strategy for a particular application. These two key metrics can also help verify the success of a chosen strategy during data recovery testing.
