DevOps/CloudGeneral
SLA / Uptime
Also written as Service Level Agreement, 99.9% uptime
An SLA is a commitment about a system's reliability (e.g. 99.9% uptime); uptime measures how much of the time a system is actually available and working.
Think of it like
Like a store's posted promise to be open 99.9% of business hours — and uptime is the receipt showing how often the doors were really unlocked.
Junior or senior?
Junior sounds like
Repeats '99.9%' as a buzzword.
Senior sounds like
Can name the actual uptime number they were accountable for, and a time they missed it.
Ask them
“What SLA was your team accountable for, and can you tell me about a time you missed it?”