Saturation Alerts vs Utilisation Alerts

Utilisation is what you have used; saturation is what you have left. Why saturation alerts fire earlier and better.

Utilisation

CPU at 80%; disk at 70%. The number you have used.

Useful for trends but late as a leading indicator.

Saturation

Queue depth, wait time, throttle events. The number telling you the resource is overloaded.

Fires earlier. CPU at 80% might be fine; queue depth growing is not.

Alert on saturation

Queue depth > N for M minutes. Pager fires before users notice.

Most teams alert on utilisation only. Add saturation alerts; the leading indicator catches issues earlier.