SLA
Service level agreement: an agreed target for a service, such as how available it must be or by what time a batch run must finish.
Also written service level agreement, SLO, service level objective, availability target
An SLA, or service level agreement, is an agreed promise about a service. It might be between an IT department and the business, or between a company and its customers or partners. Internal targets are sometimes called SLOs, service level objectives.
Typical mainframe SLAs cover a few things. Availability: online banking available 99.95% of the time outside agreed windows. Response time: most transactions completing within half a second. Batch: the end-of-day run complete by 6 a.m., or a file sent to a partner by a fixed time.
SLAs are measured, using data such as SMF and monitoring records, and reported regularly. Missing one can lead to penalties, or at least serious questions, so they shape how systems are run: WLM goals, the critical path and incident priorities all reflect them.
If you are supporting a job or service, it is worth knowing its SLA. It tells you how urgent a problem really is.
Where can I learn this hands-on?
Right here, at ZedBank. You take a junior job at a simulated bank and learn each part of the work by doing it, with Zed beside you. There's nothing to install.
Start at ZedBankRelated
- Batch windowThe period, usually overnight, in which batch work has to finish before the business needs the systems back.
- Critical pathThe chain of dependent batch jobs that decides when the whole batch run finishes; any delay on it delays the finish.
- IncidentAn unplanned interruption to a service, or a drop in its quality, which is logged, prioritised and worked on until the service is back.
- Maintenance windowAn agreed time, usually when few people use the systems, set aside for planned changes that may affect a service.
- WLMWorkload Manager: the part of z/OS that decides which work gets the processor, memory and disk access first, based on goals the site sets.