@Vikas_g1997 Out of the box, Dynatrace will leverage a baselining. This baseline is formulated over 7 days. As days elapse and you get closer to completing 7 days of baselining, the AI Baseline for the given entity gets better and better. So if your host uses 50% disk space over the past week, and that jumps up to 80%, that's 30% increase is enough of a deviation from the established baseline to trigger a problem being raised.
Yes, organizations might want a static alert in the sense that they don't want to be bothered until a threshold is met, say 10% free space left. This can also be set via the host settings under anomaly detection.