High availability is a system design approach and associated service implementation that ensures a prearranged level of operational performance will be met during a contractual measurement period.
Users want their systems, for example hospitals, production computers, and the electrical grid to be ready to serve them at all times. Availability refers to the ability of the user community to obtain a service or good, access the system, whether to submit new work, update or alter existing work, or collect the results of previous work. If a user cannot access the system, it is - from the users point of view - unavailable.
Generally, the term downtime is used to refer to periods when a system is unavailable.
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Users want their systems, for example hospitals, production computers, and the electrical grid to be ready to serve them at all times. Availability refers to the ability of the user community to obtain a service or good, access the system, whether to submit new work, update or alter existing work, or collect the results of previous work. If a user cannot access the system, it is - from the users point of view - unavailable.
Generally, the term downtime is used to refer to periods when a system is unavailable.
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