In ITIL, availability (of an IT service) can be defined as the “ability of an IT service or a component to perform it’s required function at any instant or over any period of time.”
Availability Management optimizes the capability of the IT infrastructure & services to provide a cost-effective and sustained level of (IT service) availability to support the business objectives of an organization. In other words, Availability Management manages the availability of (IT) services.
The availability of a service (or services) depends upon the IT systems that it is based on and the reliability of the ICT components as well as on the Incident, Problem and Change Management procedures.
If a service is not available due to any IT problem, it will result in at least the following:
- Loss of revenue.
- Customer dissatisfaction.
- Added costs (example overtime payments to staff)
The following definitions are important in better understanding Availability Management:
SERVICE LEVEL AGREEMENT (SLA): This is an agreement between a Service Provider and a (paying) customer which clearly documents the agreed levels of service availability. (In other words, a customer enters into a SLA with the IT service of a service provider through the Service Level Management process.)
OPERATIONAL LEVEL AGREEMENT (OLA): This is an agreement between the IT service and the internal departments in order to provide a certain service.
UNDERPINNING CONTRACTS (UCs): This is an agreement between the IT service and external teams (providers) in order to provide a certain service.
Life-cycle of the ITIL Availability Management Process:
Therefore, it implies that:
- High MTBSI = High Reliability
- Low MTTR = High Maintainability
- High MTBF = High Availability
Responsibilities of Availability Management:
- Maximizes availability of IT services by optimizing the IT infrastructure.
- Continuously tries to meet the availability requirements of the customer.
- Sets correct expectations to the customer and the service level management team about the availability levels that can be expected.
- Develop a long-term availability plan for improved IT service delivery.
- Collect, analyze and maintain availability data.
- Proactively look for cost-effective opportunities to improve availability of (IT) services.
Vital Business Functions are those services which need to be available 100% of the time. Widely used in Availability Management and IT Business Continuity Management, unavailability of these VBFs (services) will add on unacceptable costs to the organization.
The Availability Manager should actively monitor the availability levels and ensure that they are in line with the SLA. The Availability Manager should also ensure that the OLAs and UCs are also met by the respective teams.