Is there a guide or best practice on setting up metrics / thresholds in a RAC environment? (4243450)

There isn't a specific guide, or guidelines on setting up standard thresholds for alerts. Spotlight on RAC has many default alarms, you can find the details in the Help | Spotlight on Oracle RAC | Alarms section, however for some alarms, there are no pre-defined thresholds set up. You can set an alarm for a metric up by editing the thresholds, but we cannot provide the threshold values, as they will depend on the load of your environment.

You can right-click the control, and select 'Show History' for reference. By default it shows 1 hours data. You can set it to display a maximum of 1 day from the Spotlight Options | Chart configuration. There is no script to do this though, and would have to be set up on each of your connections.

As the load and values are different for all environments, this is why there is no setup guide or specific thresholds for these alarms.