4.5 AlertingPEM continually monitors registered servers and compares performance metrics against pre-defined and user-specified thresholds that constitute good or acceptable performance for each statistic. Any deviation from an acceptable threshold value triggers an alert. An alert is a system-defined or user-defined set of conditions that PEM compares to the system statistics. Alerts call your attention to conditions on registered servers that require your attention.When your system statistics deviate from the boundaries specified for that statistic, the alert triggers, displaying a high (red), low (yellow), or medium (orange) severity warning in the left-most column of the Alert Status table on the Global Overview dashboard (see Figure 4.29).The PEM server includes a number of pre-defined alerts that are actively monitoring your servers. If the alert definition makes details available about the cause of the alert, you can click the down arrow to the right of the severity warning to access a dialog with detailed information about the condition that triggered the alert (see Figure 4.30).PEM also provides an interface that allows you to create customized alerts. Each alert uses metrics defined on an alert template. An alert template defines how the server will evaluate the statistics for a resource or metric. The PEM server includes a number of pre-defined alert templates, or you can create custom alert templates. For more information about creating a custom alert template, see Section 18.104.22.168.