Application Tiering¶
- Application tiering is defined to align the operations model to supporting key Rubin processes and capabilities. This are used as decision support for the following type of scenarios:
- When there are multiple issues occurring and the team is constrained on what they can work on. Real Time applications will be prioritized over critical and operational tier applications. 
- When there are hardware issues and there are limited resources to run everything 
- During disaster recovery to prioritize which applications to restore 
 
Below are the application criticality levels. The application tiering can change over time and will change for some applications after commissioning.
| Tier | Definition | Impact of Failure | Examples | 
|---|---|---|---|
| Real Time | Essential applications for operations that are required to run real time or supports a real time application. They are required run in a time frame which is measured in minutes. | The application cannot be rerun because it is based on a real time process | Prompt Processing, QServ, Embargo Butler | 
| Critical | Essential application for operations that are not real time. An interruption is recoverable. | Can cause significant delays, disruptions, or reduced productivity | ConsDB, Panda | 
| Operational | Applications that support science functions, but are not considered essential for the immediate functioning of work. | May cause disruptions, but not major ones | Exposurelog |