5.2Service Management

A system only delivers value through ongoing operation that continues to provide value, not just through being built. Among the service management practices that ITIL organizes, distinguishing incident/problem/change management and availability calculations (from MTBF/MTTR, and combining series/parallel configurations) are recurring, important domains on the AP exam.

5.2.1ITIL and SLA/SLM

• ITIL (Information Technology Infrastructure Library) is a collection of best practices for IT service management and a de facto international standard. Using the service lifecycle (strategy -> design -> transition -> operation -> continual improvement) or, more recently, the service value system, it treats everything from service planning to improvement as a continuous cycle.
• SLA (Service Level Agreement) is a formal agreement between provider and user that documents target service quality levels (availability, response time, recovery time, and so on). SLM (Service Level Management) is the management process that continuously monitors, reports on, and improves the targets defined in the SLA. The distinction: an SLA is "the content of the promise," while SLM is "the mechanism that keeps the promise over time."