o answer this we need to look at response times: If response times are so long that use of a service, website, transaction or similar becomes impossible, PerformanceGuard considers the service, etc. to be unavailable.
By default, PerformanceGuard loses its patience with a service, etc. if it hasn't responded within 500,000 milliseconds (that's a little more than eight minutes).
Everything that's not unavailable, is considered by PerformanceGuard to be available. So, if you see that a service has been 100% available during the last week, it means that it has not exceeded the acceptable response time limit during the last week.