Switchover is the manual switch from one system to a redundant

Redundancy (engineering)

In engineering, redundancy is the duplication of critical components or functions of a system with the intention of increasing reliability of the system, usually in the case of a backup or fail-safe....

 or standby computer

Computer

A computer is a programmable machine designed to sequentially and automatically carry out a sequence of arithmetic or logical operations. The particular sequence of operations can be changed readily, allowing the computer to solve more than one kind of problem...

 server

Server (computing)

In the context of client-server architecture, a server is a computer program running to serve the requests of other programs, the "clients". Thus, the "server" performs some computational task on behalf of "clients"...

, system

System

System is a set of interacting or interdependent components forming an integrated whole....

, or network

Computer network

A computer network, often simply referred to as a network, is a collection of hardware components and computers interconnected by communication channels that allow sharing of resources and information....

 upon the failure or abnormal termination

Abnormal end

An ABEND is an abnormal termination of software, or a program crash.This usage derives from an error message from the IBM OS/360, IBM zOS operating systems. Usually capitalized, but may appear as "abend"...

 of the previously active server, system, or network, or to perform system maintenance, such as installing patches, and upgrading software or hardware.

Automatic switchover of a redundant system on an error condition, without human intervention, is called failover

Failover

In computing, failover is automatic switching to a redundant or standby computer server, system, or network upon the failure or abnormal termination of the previously active application, server, system, or network...

. Manual switchover on error would be used if automatic failover is not available, possibly because the overall system is too complex.

See also

• Safety engineering
  Safety engineering
  Safety engineering is an applied science strongly related to systems engineering / industrial engineering and the subset System Safety Engineering...
  
  
• Data reliability
• Fault-tolerance
• HA Clusters
  High-availability cluster
  High-availability clusters are groups of computers that support server applications that can be reliably utilized with a minimum of down-time. They operate by harnessing redundant computers in groups or clusters that provide continued service when system components fail...
  
  
• Business continuity planning
  Business continuity planning
  Business continuity planning “identifies [an] organization's exposure to internal and external threats and synthesizes hard and soft assets to provide effective prevention and recovery for the organization, whilst maintaining competitive advantage and value system integrity”. It is also called...