When designing a solution, what defines the length of time that is acceptable for a business to be without a specific application?

Call to repair refers to the act of contacting support to initiate a fix, not a defined tolerance threshold for application downtime.

Response time is a performance metric measuring system or network latency under normal operation, not an outage tolerance definition.

SLO (Service Level Objective) is a performance target within a broader SLA but does not specifically quantify the acceptable length of application unavailability.

RTO (Recovery Time Objective) is a disaster recovery metric that specifies the maximum acceptable downtime for a business application or process following a failure or disaster event. It is established during business impact analysis and directly drives recovery architecture decisions such as failover speed, replication frequency, and infrastructure investment.