Identifying Vital Business Functions (VBFs)
The term Vital Business Function (VBF) is used to reflect the business critical elements of the business process supported by an IT service. The service may also support less critical business functions and processes, and it is important that the VBFs are recognized and documented to provide the appropriate business alignment and focus.
Designing for availability
The level of availability required by the business influences the overall cost of the IT service provided. In general, the higher the level of availability required by the business, the higher the cost. These costs are not just the procurement of the base IT technology and services required to underpin the IT infrastructure. Additional costs are incurred in providing the appropriate Service Management processes, systems management tools and high-availability solutions required to meet the more stringent availability requirements. The greatest level of availability should be included in the design of those services supporting the most critical of the VBFs.
When considering how the availability requirements of the business are to be met, it is important to ensure that the level of availability to be provided for an IT service is at the level actually required, and is affordable and cost-justifiable to the business. Figure 4.17 indicates the products and processes required to provide varying levels of availability and the cost implications.
Figure 4.17 Relationship between levels of availability and overall costs
Base product and components
The procurement or development of the base products, technology and components should be based on their capability to meet stringent availability and reliability requirements. These should be considered as the cornerstone of the availability design. The additional investment required to achieve even higher levels of availability will be wasted and availability levels not met if these base products and components are unreliable and prone to failure.
Systems management should provide the monitoring, diagnostic and automated error recovery to enable fast detection and speedy resolution of potential and actual IT failure.