• Ups Uptime Calculator

Systems with high up-time, a.k.a. 'always on'High availability ( HA) is a characteristic of a system, which aims to ensure an agreed level of operational performance, usually, for a higher than normal period.Modernization has resulted in an increased reliance on these systems. For example, hospitals and data centers require high availability of their systems to perform routine daily activities. 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 is used to refer to periods when a system is unavailable.

Contents.Principles There are three principles of in which can help achieve high availability. Elimination of. This means adding redundancy to the system so that failure of a component does not mean failure of the entire system.

Reliable crossover. In, the crossover point itself tends to become a single point of failure. Reliable systems must provide for reliable crossover. Detection of failures as they occur. If the two principles above are observed, then a user may never see a failure – but the maintenance activity must.Scheduled and unscheduled downtime. This section does not any.

Ups Uptime Calculator

Unsourced material may be challenged and.Find sources: – ( June 2008) A distinction can be made between scheduled and unscheduled. Typically, is a result of that is disruptive to system operation and usually cannot be avoided with a currently installed system design. Scheduled downtime events might include patches to that require a or system configuration changes that only take effect upon a reboot. In general, scheduled downtime is usually the result of some logical, management-initiated event. Unscheduled downtime events typically arise from some physical event, such as a hardware or software failure or environmental anomaly. Examples of unscheduled downtime events include power outages, failed or components (or possibly other failed hardware components), an over-temperature related shutdown, logically or physically severed network connections, security breaches, or various, and failures.If users can be warned away from scheduled downtimes, then the distinction is useful. But if the requirement is for true high availability, then downtime is downtime whether or not it is scheduled.Many computing sites exclude scheduled downtime from availability calculations, assuming that it has little or no impact upon the computing user community.

By doing this, they can claim to have phenomenally high availability, which might give the illusion of. Systems that exhibit truly continuous availability are comparatively rare and higher priced, and most have carefully implemented specialty designs that eliminate any and allow online hardware, network, operating system, middleware, and application upgrades, patches, and replacements. For certain systems, scheduled downtime does not matter, for example system downtime at an office building after everybody has gone home for the night.Percentage calculation Availability is usually expressed as a percentage of uptime in a given year.

The following table shows the downtime that will be allowed for a particular percentage of availability, presuming that the system is required to operate continuously. Often refer to monthly downtime or availability in order to calculate service credits to match monthly billing cycles. The following table shows the translation from a given availability percentage to the corresponding amount of time a system would be unavailable.