Disaster Recovery Basics - CompTIA Tech+ Study Guide
Why Disaster Recovery is Important
Disaster recovery is a critical component of any organization's IT strategy. Data loss can occur due to natural disasters, cyberattacks, hardware failures, or human error. Having a solid disaster recovery plan ensures business continuity, protects valuable data assets, minimizes downtime, and helps organizations meet regulatory compliance requirements. For IT professionals, understanding disaster recovery basics is essential for protecting organizational resources and maintaining operational stability.
What is Disaster Recovery?
Disaster recovery (DR) refers to the set of policies, tools, and procedures designed to enable the recovery or continuation of vital technology infrastructure and systems following a natural or human-induced disaster. It focuses specifically on the IT systems that support critical business functions.
Key components include:
- Recovery Point Objective (RPO): The maximum acceptable amount of data loss measured in time. This determines how frequently backups should occur.
- Recovery Time Objective (RTO): The maximum acceptable downtime before systems must be restored and operational.
- Backup Systems: Copies of data stored in separate locations for restoration purposes.
- Failover Systems: Redundant systems that take over when primary systems fail.
- Disaster Recovery Site: An alternate location where operations can continue during a disaster.
How Disaster Recovery Works
1. Risk Assessment and Business Impact Analysis
Organizations identify potential threats and evaluate how different disasters would affect operations. This helps prioritize which systems need the fastest recovery.
2. Developing the DR Plan
A comprehensive plan documents procedures for responding to various disaster scenarios, including roles and responsibilities, communication protocols, and step-by-step recovery procedures.
3. Backup Strategies
- Full Backup: Complete copy of all data
- Incremental Backup: Only backs up data changed since the last backup
- Differential Backup: Backs up all changes since the last full backup
4. Types of Recovery Sites
- Hot Site: Fully equipped and operational, can take over almost instantly
- Warm Site: Partially equipped, requires some setup time
- Cold Site: Basic facility with power and connectivity, requires significant setup
5. Testing and Maintenance
Regular testing ensures the DR plan works as expected. This includes tabletop exercises, simulations, and full-scale tests.
The 3-2-1 Backup Rule
A widely accepted best practice:
- 3 copies of your data
- 2 different storage media types
- 1 copy stored offsite or in the cloud
Exam Tips: Answering Questions on Disaster Recovery Basics
Focus on Definitions
Know the precise meanings of RPO and RTO. RPO relates to data loss tolerance, while RTO relates to downtime tolerance. Questions often test whether you can distinguish between these two concepts.
Understand Backup Types
Be clear on the differences between full, incremental, and differential backups. Remember that incremental backups are faster to create but slower to restore, while differential backups grow larger over time but restore more quickly than incremental.
Know Your Recovery Sites
Hot sites are the most expensive but provide the fastest recovery. Cold sites are the least expensive but require the most time to become operational. Expect questions comparing cost versus recovery speed.
Think About Real-World Scenarios
When presented with scenario-based questions, consider what type of disaster is described and match it to the appropriate response. A financial institution with zero tolerance for downtime would need a hot site, for example.
Remember the 3-2-1 Rule
This is a frequently tested concept. Make sure you can identify correct implementations of this backup strategy.
Consider Cost-Benefit Trade-offs
Questions may ask you to recommend solutions based on budget constraints or business requirements. Balance recovery speed needs against available resources.
Review Common Terminology
Familiarize yourself with terms like failover, redundancy, replication, and business continuity. Understanding how these relate to disaster recovery helps with contextual questions.