The hot standby mode is a fail-safe in which a hot standby component is part of an active system. If any component of the system fails, the hot standby component takes its place. In general,a hot standby can refer to any device,system etc. that overtakes operation from a failed device and reduces the startup delay that would otherwise be huge.
A figure to further explain the hot standby mode is as follows −
In general, it is expected that a system will have some failures. So, a hot standby is necessary to combat these failures.
At the extreme, a hot standby can be a duplicate system that is kept as up to date as the active system. If the active system fails, it can be substituted by the hot standby system. But more commonly a hot standby is an important component of the active system. If this component fails in the system, it can be replaced by the hot standby component.
This makes sure that the system is offline for as short a time as is possible.
The uses of hot standby mode are as follows −