Deleting a service group for the Search service application is required in the following scenarios:
When you want to modify the application
After deleting a service group, you need to remount the volumes that were taken offline by the wizard.
When you decide to stop monitoring the application
When you delete a service group using the wizard, all the resources are taken offline. Any new search queries will fail, because the index locations are unavailable. To continue processing queries further, you need to remount the volumes that were taken offline by the wizard.
To delete a service group using the wizard
All the service groups that are configured in the cluster are listed.
Select the service group that you want to delete, and click Next.
When the last service group for a Search service application is deleted from a cluster node, the node is removed from the system list of the SharePointSearch-QueryProcessor service group.
After all the service groups for a Search service application in the cluster are deleted, the SharePointSearch-QueryProcessor service group is also deleted.