In others, performance penalties or increased hardware and software costs may be incurred so that major systems management problems can be avoided. In a multi-system environment, each system must have its own terminal network service machines, network domains, and network connection hardware. In addition, the user community must be partitioned among the systems, and each user must know which system to access and how to do so. If the distribution of users on systems changes, perhaps because of capacity considerations, new procedures must be provided to the affected users, who must be sure to follow them. These requirements reduce the flexibility organizations can bring to the management of VM multiple-system environments.
Costs are higher because additional network hardware and software are required.
Ease of use is reduced because users must be familiar with the system configuration. Capacity may be artificially constrained because optimal load balancing cannot be achieved. Performance may be reduced by the need to support multiple network service virtual machines. Network configuration and management may be more complex because resources must be partitioned among the VM systems. As a result, only one domain is required for each terminal network and all users of that network access the complex using the same procedure.