A  sustainable application consolidation has as its two-fold goal the reduction of maintenance costs for existing IT applications in combination with the opening up of maneuvering room for future decisions in IT operations. During an application consolidation, for example, redundant IT functions can be merged into a single form of the IT function which is used in parallel – the oft-quoted „service-oriented architecture“: ­encapsulation of an application function and the utilization of this service by a large number of consumers in lieu of redundant function implementation in separate applications.  

Whether alternative or parallel, a rise in the average utilization of infrastructure capacity can be pursued as a consolidation approach. This is achieved by the pooling of a number of applications on one server by means of server virtualization or of the reduction in the total number of server systems in use by migration to fewer, but larger, server modules for the required applications.

Structured application consolidation must ensure that there is no long-term impairment of the affected business processes ­during the replacement of obsolete system components or ­migration between server systems and that neither functions nor data are lost (see Figure 1). 

Monolithic systems offer high performance capabilities   

However, cost optimization through application consolidation is made more difficult by existing performance requirements on their infrastructure coming from the applications in use. ­Owing to their functional scope which has built up over time, the complexity of internal dependencies, or existing architectural shortcomings, applications often take the form of large, monolithic application systems. These monolithic applications are characterized by large mainframes, Unix hosts, or „high-end“ servers which provide the run-time environment for the complex processes of the applications by using a large number of CPUs and plenty of RAM in an operating system environment.