Disaster recovery

HA is not DR. They have similar objectives: business continuity and minimizing downtime. The difference between HA and DR is that DR focuses on policies and procedures to enable the recovery of the system, application, or entire data center to a fully operational state after a catastrophic event. Similar to HA, there are SLAs that help define requirements for DR, which, in turn, determine the policies, procedures, strategy, and even implementation details to meet the needed SLAs. Two important terms help define the DR requirement: Recovery Point Objective (RPO) and Recovery Time Objective (RTO).

RTO measures how quickly the system, application, or data center can be restored. This measurement of time for recovery is not only about restoring the application to a functional state to resume critical business processes but also about the data.

RPO is the enterprise measurement of data loss tolerance. How much data can the enterprise afford to lose without it having...