System Availability is also affected by reliability, manageability, serviceability, performance, and security. It’s worth mentioning that systems that are insecure may be liable to attacks that compromise the availability of the system. Therefore, having a good availability management system will ensure that all IT infrastructure, tools, processes, and roles are suitable for the agreed service level targets for availability.

For example, an engineer, depending on the availability requirements of the particular service, can make the relevant decisions for his/her replicated application configuration. The decision will be highly influenced by how critical is the delivery of that services; hence, how fast are the desired reactions to failures. The decision is also dependent on how much latency can the client tolerate when receiving a reply to a request in a no-failure scenario.

System Availability assessment is mainly carried out to improve system availability, recovery times, minimizing the risk of lost revenues, and reducing costs due to downtime. Like the reliability and DR plans, system availability review involves analyzing the current availability assessment plan to:
  • Determine whether the IT processes are adequate to support current and future business needs. That is, in regards to the times of the day the system is expected to be operational.
  • Help identify root causes of outages, i.e. failure point assessment: How long can an outage last if one does occur? How about scheduled outages?
  • Perform process review assessment that offers a broad view of the current IT system and helps expose availability risks and issues such as: How often does the system tolerate outages during the times that the system or applications are in use? When are the scheduled systems downtimes? Is it once every week over the weekend? 
  • Who is responsible for system availability assessment?
  • Verify that you have appropriate IT support vendor agreements in place. This is to ensure expedient support in case of failure.
  • What is the crisis communication plan when the system is unavailable?
  • Etc…