I am trying to understand what factors impact the performance of a criteria based group. I have read that member size has direct impact, but it does not make much sense, When a resource is updated, FIM looks for all criteria based groups that have criteria containing the attributes updated in the resource and recalculates the membership of those groups. So my understanding is that the performance of criteria based group is dependent on the criteria, not on the member size of the group. If you have a lot of criteria, then FIM will spend more time on evaluating the criteria and the chance of matching the attribute with the attributes updated in a resource will increase. The member size should not have much impact here.

Yes, member size can be an issue, but that will not be limited to a criteria based group - that should apply to any groups with large number of members. Because that impacts the memory footprints and complexity of membership calculation both in Sync and in AD.

Is my understanding correct, or I am missing something?

• Edited by Just Another FIM Guy Thursday, September 18, 2014 1:55 AM

Unless FIM checks if the user already exists in the group prior to applying the criteria, in which case the number of members could have a slight impact but I'm not sure - will be good to know the answer too, but I think it should be only dependant on the criteria

If you have a lot of criteria, then FIM will spend more time on evaluating the criteria and the chance of matching the attribute with the attributes updated in a resource will increase.

For this, I know that in FIM 2010 R2 a new optimization feature came which fetches the information of "Common Criteria" from maximum number of groups and sets and uses this feature for calculating the group membership in a much faster way which enhances the performance.

You can also, use the Deferred option in groups for calculating group membership. It is also a feature of FIM 2010 R2 for better performance.

http://technet.microsoft.com/en-us/library/jj863243(v=ws.10).aspx