SLAs use service quality metrics to express measurable QoS characteristics. Select two metrics from the list and provide a descriptive explanation of the importance of including these metrics in the SLA.
Please indicate the priority that should be placed on the metrics you selected when negotiating an SLA. 

Availability “ up-time, outages, service duration 
Reliability “ minimum time between failures, guaranteed rate of successful responses 
Performance “ capacity, response time, and delivery time guarantees 
Scalability “ capacity fluctuation and responsiveness guarantees 
Resiliency “ mean-time to switchover and recovery
Security “ security measures such as anti-virus updates and patching

 *please remember to include at least one credible scholarly reference with your initial post!