What is disaster recovery with example?

Disaster recovery refers to the strategies and plans in place to restore IT infrastructure and systems after a natural or human-induced disaster. The goal of disaster recovery is to minimize downtime and data loss in the event of system failures or disruptions. An effective disaster recovery plan ensures critical systems can resume normal operations as quickly as possible following an outage.

What are the key elements of a disaster recovery plan?

A comprehensive disaster recovery plan will include the following key elements:

  • Business impact analysis – Identifies the potential impact of system downtime on business operations. This helps prioritize systems and set recovery time objectives.
  • Recovery strategies – Specifies strategies for restoring systems, such as using redundant servers, backups, or alternative sites.
  • Detailed recovery plans – Provides step-by-step procedures for recovering systems, applications, and data to meet RTOs.
  • Emergency response – Defines the immediate actions, roles, and notifications required in response to a disaster.
  • Testing – Validates the effectiveness of disaster recovery strategies through simulated outages.
  • Awareness training – Educates staff on disaster response procedures and responsibilities.
  • Maintenance – Ensures the DR plan is kept current with any changes to the IT environment.

What are some key disaster recovery strategies?

Common disaster recovery strategies include:

  • Backup and restore – Regularly backing up critical data, systems, and applications and storing the backups offline. Backups can be used to restore systems after data loss or corruption.
  • Redundant infrastructure – Maintaining duplicate systems, servers, and network connections that can take over in the event of failures.
  • Failover – Automatically switching operations to redundant systems when primary systems fail.
  • Hot sites – Maintaining fully equipped, live data backup sites that can be operational immediately.
  • Warm sites – Backup facilities with power, networks, and basic equipment but which need some provisioning.
  • Cold sites – Facilities with adequate space and infrastructure but no computer systems.
  • Disaster recovery as a service (DRaaS) – Leveraging cloud-based DR services rather than managing internal hot sites.

Why is disaster recovery important for businesses?

There are several reasons why disaster recovery planning is critical for organizations:

  • It minimizes downtime and promotes business continuity when disasters occur. This avoids revenue and productivity losses.
  • It protects critical data and assets that would be difficult or impossible to replace.
  • It maintains communications and operations until regular business processes resume.
  • It upholds legal, regulatory, and contractual obligations for availability and data security.
  • It protects a company’s reputation by showing customers and partners it can effectively respond to crises.
  • It reduces liabilities associated with system failures affecting customers or partners.

What are recovery time objectives (RTO) and recovery point objectives (RPO)?

RTO and RPO are important metrics used to measure the effectiveness of disaster recovery strategies:

  • Recovery time objective (RTO) – The maximum tolerable time before a business process or system must be restored after a disruption. For example, a company may set an RTO of 24 hours for full restoration of email services.
  • Recovery point objective (RPO) – The maximum tolerable period during which data can be lost from a disaster event. This is based on the frequency of backups. For instance, a company may have an RPO of 4 hours if performing incremental backups every 4 hours.

When defining RTOs and RPOs, companies analyze the potential business impact and financial losses associated with varying levels of downtime. More critical systems will have shorter RTOs and RPOs.

What are some potential disasters that could cause system outages?

Disaster recovery plans should account for a wide range of potential catastrophes including:

  • Natural disasters – Hurricanes, floods, earthquakes, tornadoes, severe storms etc.
  • Power outages – Short and long-term power failures.
  • Fire – Equipment fires, building fires, wildfires etc.
  • Hardware failures – Server, storage, network device malfunctions.
  • Software failures – Software bugs, code errors, security flaws.
  • Human errors – Accidental deletions, configurations, sabotage.
  • Cyber attacks – Malware, hacking, ransomware, DDoS attacks.
  • Communication outages – Loss of internet, WAN, LAN, voice.
  • Supply chain disruptions – Manufacturing, shipping, transportation issues.
  • Pandemics – Health crises that restrict access to facilities.
  • Loss of utilities – Disruptions to electricity, gas, water supplies.

What are the steps in the disaster recovery process?

When disaster strikes, the recovery process generally involves the following key steps:

  1. Initial emergency response – Executing initial actions to protect life and safety, damage assessment, and declaring a disaster scenario has occurred.
  2. Activation of recovery plan – Formally activating the disaster recovery plan based on damage assessments and predefined triggers.
  3. Recovery of critical systems – Restoring core systems needed to resume priority business operations and meet RTO objectives.
  4. Full infrastructure recovery – Progressively restoring remaining infrastructure, systems, and data to normalized working state.
  5. Normalization of operations – Returning to standard business operations once critical services have been restored.
  6. Deactivation – Standing down disaster recovery resources once recovery is complete.
  7. Lessons learned – Documenting challenges and successes during the recovery to identify improvements for future plans.

What is a disaster recovery plan test?

Disaster recovery testing involves simulations to validate the effectiveness of disaster recovery strategies within an organization. Different types of disaster recovery tests include:

  • Walkthroughs – Teams discuss recovery procedures but do not perform any actions.
  • Tabletop exercises – Simulated scenarios presented to teams to assess responses.
  • Checklists – Validating ability to follow documented recovery checklists.
  • Component testing – Testing recovery of specific systems or hardware in isolation.
  • Parallel testing – Operating systems at an alternate site in parallel with primary site.
  • Full interruption testing – Completely shutting down a primary site and failing over to alternate systems.

Frequent disaster recovery testing provides assurance that recovery strategies will work effectively during actual outages. It also helps identify plan gaps and areas for improvement.

Example: Disaster recovery plan for an online retailer

Here is an example disaster recovery plan for an ecommerce company that sells products online and maintains a website, database servers, and inventory management systems:

Business Impact Analysis

The potential impact of system downtime has been analyzed:

  • Website outage will result in immediate loss of sales revenue.
  • Unavailability of order databases disables order fulfillment processes.
  • Inventory system downtime prevents warehousing operations.
  • Prolonged downtime will damage company reputation.

Recovery Strategies

  • Cloud-based website failover – Website is failing over to cloud-hosted replica site when primary data center is down.
  • Database replication – Databases are replicated in real-time to offsite disaster recovery data center.
  • Redundant inventory system – Inventory system has onsite redundancy and spare parts if hardware fails.
  • Offsite backups – Daily backups of databases and software are taken to secure offsite location.

Emergency Response

If systems outage is detected:

  1. Alert IT managers immediately.
  2. Determine cause of outage based on health indicators.
  3. Declare a disaster if criteria met for failover to recovery site.
  4. Activate disaster recovery team and procedures.

Recovery Time Objectives

  • Website failover – Within 1 hour
  • Order database availability – Within 2 hours
  • Inventory system recovery – Within 24 hours

Roles and Responsibilities

Role Responsibilities
Disaster recovery manager Triggers activation of disaster recovery plan and oversees execution of procedures.
Network administrator Implements failover between primary and secondary sites and restores network functionality.
System administrator Recovers server systems from backups and ensures applications are available at secondary site.
DBA Orchestrates database failover and verifies data recovery at DR site.
Security officer Oversees potential cyber attack response and ensures systems are secure.


Effective disaster recovery is vital for organizational resilience when disruptions occur. A comprehensive disaster recovery plan will protect critical systems and data and provide a detailed roadmap for responding to outages. Key elements include continuity strategies, emergency procedures, defined roles, and regular testing. With diligent preparation, companies can minimize the business impacts of inevitable disruptions.