When using System Center Operations Manager (SCOM) to monitor Active Directory with Client Side monitoring the following warning could appear in the console
AD Client GC Availability : There are not enough GCs available. There are fewer GCs configured than are specified as the minimum number of available GCs. Available GCs: 1 Minimum GCs: 3
As the error message implies the number of GCs is too low according to rule’s best practice, image above is coming from my PoC lab where only a single DC/GC is currently installed.
Navigating to Authoring / Management Pack Object / Monitors you can see the rule is actually disabled
In SCOM multiple workflows and rules can share a single data source which can be something as simple as a script. In the ADMP there is a collection rule named AD Client GC Availability PerformanceCollection which is causing the warning generation.
To get rid of the warning message you can either disable this rule in case it is not valuable for your monitoring strategy or you can create an override for it so to adjust the minimum number of GCs to a more reasonable number.
Navigate to Authoring / Management Pack Objects / Rules and locate the AD Client GC Availability PerformanceCollection double-click on it (or right-click and select properties) and on the Overrides tab create an override
In the Override Properties set the desired value for the number of GC to look for in my lab I’ve set this to 1
Once you click OK and the new the rules are deployed to the monitored agent the There are not enough GCs available warning message can be closed and will stop repeating.
On a closing note keep in mind the rule described in the article can or cannot be of interest in your particular deployment. In my experience latter case is the most commons and it is usually easier and faster to simply disable the collection rule all together.