High availability and scaling in cloud environments

Business continuity

• The strategy and processes aimed at ensuring a business remains functional in some capacity during or after a critical incident. It encompasses more than just compute infrastructure or data centers and can apply to various aspects of a business, including office space, management resource redundancy, and finances

• How to keep the business functional in some capacity during/after a critical incident

Disaster recovery (DR)

• The process of saving and recovering data and other critical business processes during or after a critical incident. It involves having a well-defined plan or playbook with steps to follow for recovery, which directly contributes to business continuity.

• How to save and recover data and other business processes during/after a critical incident. Contributes to the Business Continuity plan

Recovery Time Objective (RTO)

A time-based metric that defines the maximum acceptable amount of time since the last data recovery point. RPO specifies the maximum data loss that is deemed acceptable in terms of time

High Availability (HA)

The characteristic of a system where it continues to function despite the complete failure of any component within the architecture. However, HA acknowledges that there may be an interruption of service, but it should not exceed the time linits defined by the RTO

Redundancy

Closely related to high availability but differs in that it ensures a system continues to function without degradation in performance even in the event of a complete component failure. Redundancy does not imply any interruption of service and is typically more challenging to achieve than simple high availability