Targeting a computer group in Operations Manager 2007 produces unexpected results because the computer group target (that is, the class of objects that are computer groups), only exists on the root Management Server. Therefore, any rule that you target to this object class attempts to collect event information from the root Management Server. In some cases, the root Management Server might not have the instrumentation that the rule depends on. For example, a rule that depends on IIS metrics will not be able to collect any information on a root Management Server that has no IIS server on the computer. In other cases, you might collect information that is not what you expect because the rule is intended to collect data on a machine other than the root Management Server.
The only way to send rules to specific computers is to target the rule to an object that exists on the computer, such as a SQL Server object or an IIS Web site object. You can then use overrides to specify the places where the rule works.
For example, consider the scenario where you want to target a rule to all Windows Server 2003 servers that are in a particular computer group. To do this, complete the following steps:
1. Create a rule that is targeted to the Windows Server 2003 class.
2. Set the rule so it is not enabled by default.
3. Create an override that will enable the rule only for objects that are members of the desired group.