You can use performance alerts to notify you and others when certain events occur or when certain performance thresholds are reached. You can also use performance alerts to generate events that are logged in the Application event log and to start applications and performance logs.

After you select the Alerts node in the left pane of Performance Monitor, you should see a list of current alerts (if any) in the right pane. A green log symbol next to an alert, as shown in the following screen, indicates it is active. A red log symbol indicates the alert is inactive and won't be triggered even if the performance alert condition is reached.

You can manage an existing alert by right-clicking its entry in the right pane and then selecting one of the available shortcut options. Choose Delete to delete the alert. Choose Properties to display the alert's Properties dialog box. Choose Start to activate the alert. Choose Stop to stop the alert. Choose Save Settings As to save the alert configuration as a Web page that can be viewed in a browser, such as Internet Explorer, or imported into a new alert by using the New Alert Settings From option.

You can create a new alert by right-clicking in the right pane and selecting New Alert Settings from the shortcut menu. A New Alert Settings dialog box is displayed asking you to name the new alert. Type a descriptive name here before continuing, and then click OK. A Properties dialog box similar to the one in Figure 16-11 is displayed.

Figure 16-11. Create a new alert by adding counters and setting the alert conditions for those counters

Click Add to display the Add Counters dialog box, then add the counters for which you want to define alert conditions. When you are finished, click Close to return to the Properties dialog box of the alert. In the Counters panel, select the first counter, and then use the Alert When Value Is box to specify when an alert for this counter is triggered. Alerts can be triggered when the counter is over or under a specific value. Select Over or Under, and then set the trigger value. The unit of measurement is whatever makes sense for the currently selected counter(s). For example, to alert if the available megabytes of memory is less than 50, you would select Under and then type 50. Repeat this process to configure other counters you've selected.

In the Sample Data Every box, type in a sample interval, and select a time unit in seconds, minutes, hours, or days. The sample interval specifies how frequently the alert condition is checked for. By default, each counter will be sampled once every 5 seconds. Because you don't want to overburden the system by checking alert conditions, you should set a sampling interval that makes the most sense given the counters you are tracking and the load on the system.

In the Run As box, type the name of the account under which the counter log will run, and then click Set Password. After you type the password for the account and then confirm the password, click OK to close the Set Password dialog box. To run alert logging under the default account, Network Service, type <Default>.

Next, select the Action tab, as shown in Figure 16-12. You can now specify any of the following actions to happen when an alert is triggered:

Figure 16-12. Set the actions to take if the alert is triggered

When you've set the actions to use, click the Schedule tab, and then specify when alerting should start and stop. You can configure the alerting to start manually or automatically at a specific date. Select the appropriate option, and then specify a start date if necessary.

Once alerting is started, it will continue until you manually shut it off. Unlike performance logs, for which you usually want a specific stop date, you will usually want performance alerts to keep running. That way, you can be sure you will be alerted if a performance condition is met. Click OK when you are finished setting the alerting schedule and the new alert will be added to the Alerts list. The alert's icon will be red until alerting starts.