This paper describes the final results of an assessment of the scalability of an NT Cluster architecture for very large Telecommunications Call Detail Record (CDR) databases¹. The IBM DB2 DBMS was used on top of four standard Windows NT multi-processor computers to investigate the data warehousing capabilities of such an off-the-shelf solution. First a description of the experiment case and experiment set up is given. Next the results of the experiments are described. The paper ends with a conclusion on the manageability, robustness and scalability of the NT Cluster architecture for very large CDR stores.