Estimating the Utilization of Shared DASD: A Performance Management Perspective

Shared DASD are widely used to provide access to data from multiple, computer systems. Since shared DASD can be a performance bottleneck, it is important to know their utilizations. However, for some computer systems, such as the IBM operating system VM SP HPO (Virtual Machine System Product with High Performance Option), the standard measurement facilities do not provide the information necessary to calculate shared DASD utilizations. This paper presents two techniques for estimating shared DASD utilizations, and evaluates the accuracy of these techniques fcr a production workload.