hot standby

Hot standby is a standby function of components, devices and systems that can be used immediately. It serves as a redundancy function and as an energy-saving function.

1. In many systems, redundant components are in hot standby and then become active as soon as a component of the active system fails. This is the case in fault-tolerant systems, where the hot standby components - switches, routers, backup servers - remain in a wait-and-see mode as long as the active primary component is working properly. Only when the primary component or transmission link fails does the hot standby component spring into action and take over the primary component's function. Such hot standby devices are used wherever data or other information could be lost, such as in fault-tolerant storage systems.
2. In microwave technology, a hot standby is a redundant receiving device consisting of a primary unit and a secondary unit. If the primary unit malfunctions, operation automatically transfers to the secondary unit.
3. In computers and communication systems, hot standby is also used as an energy-saving function. In this case, unused components or peripheral devices can remain in energy-saving standby mode as long as they are inactive. The energy-saving function is controlled by the power management and differentiates between sleep mode, hibernation, idle state and power-down mode.