Five 9s isn't enough
Go beyond 9s service level objectives, recovery time objectives and recovery point objectives. Improve your resilience decisions with failure impact narratives.
Most organizations set some form of resilience objectives using service level agreements (SLA) in 9s notations. Some organizations formalize their recovery time objectives (RTO) to determine how long it should take an application to recover or take recovery point objectives (RPO) to determine how much data can be lost in the event of failure. A few organizations write pages of detailed non-functional resilience requirements. SLAs, RTOs, RPOs and requirements aren’t enough information to decide how much effort and money an organization should spend on resilience.