Sometimes it can be difficult to see the business forest for the IT trees. If you’ve ever pored over availability management as part of ITIL (Information Technology Infrastructure Library) best practices and wondered “why?”, here’s the answer. It’s to help prevent your enterprise from suffering catastrophic failure, a.k.a. going pear-shaped or going down the tubes. The specifications of IT availability must always be mapped onto business needs and vice versa. The following examples may help to see how.
We consider how each of the six aspects of availability in ITIL corresponds to the example of a critical ecommerce system and/or a less critical accounting system.
- Maintainability. This is the ease with which an IT component can be maintained, either proactively or reactively. Hot swap or changeovers are likely to be required for the ecommerce system, or hot failover to a backup system otherwise.
- Recoverability. The time to restore an IT component to its working state, after failure. For the ecommerce system, this may need to be a matter of minutes. For the accounting system, several hours may be acceptable.
- Reliability. The time during which an IT component should work without failure under given conditions. The ecommerce system should be continually available. If its constituent components cannot offer sufficient reliability, redundant components may be necessary.
- Resilience. The ability to resist failure. If several instances of the ecommerce system are running and one fails, it may be enough for the others to take up the load, perhaps at the expense of losing the content of some users’ shopping caddies. The accounting system may have less stringent requirements.
- Security. The ability of IT components to resist security breaches. This may affect both the ecommerce and the accounting systems equally, as both can contain confidential data on customers, company finances, or both.
- Serviceability. The availability of an IT component or service provided by a third party. A payment gateway for the ecommerce system is one example, needed availability as good as for the ecommerce system itself.
This shows how ITIL components can be mapped onto business requirements. The converse must also be confirmed, i.e. every business requirement is properly supported by IT availability, as appropriate.