There are multiple situations where it will be required to change the “All Management Servers Resource Pool” membership from automatic to manual. From part 1 of this series see: http://blogs.catapultsystems.com/cfuller/archive/2012/07/24/automatic-and-manual-resource-pools-in-operations-manager-2012-scom-sysctr.aspx
What situations require these types of changes to the resource pools?
1) Network Monitoring Management Servers should be removed from the default pools per Microsoft documentation.
2) The Orchestrator server may benefit from the Operations Manager Management Server installation. [UPDATE: Please note that it is NOT required to install a full management server on the Orchestrator server – only the OpsMgr console is required for the OpsMgr 2012 Integration Pack. However, there is a benefit to having this as a management server as well since you can point the runbooks and integration packs to the local server which has access to the OperationsManager database]
3) This may also apply for Management Servers which are dedicated to a specific Operations Manager function such as monitoring Linux/Unix systems or Veeam collectors which are installed on Management Servers.
However, if resource pools are converted to a manual membership, there are alerts which occur in OpsMgr as a result of the expectation from OpsMgr that all management servers will be a member of the “All Management Servers Resource Pool”.
As an example, with four management servers in an environment the goal was to change membership so that only the 1st and 4th server would be part of the “All Management Servers Resource Pool”. We converted this resource pool to manual and changed membership as shown below:
Soon after this change we started receiving run-as errors associated with our management servers and the data warehouse action account. To fix these situations, we added the management servers which were reporting these errors to the distribution for the Data Warehouse Action Account as shown below.
Thank you to Paul Johnson for championing this and providing a path to make this work!
Summary: When changing the membership for the “All Management Servers Resource Pool” the credentials for the Data Warehouse Action Account need to be distributed to the management servers which were removed from the resource pool.