Glossary Updates12 new terms added to the glossaries · October 2, 2026, 22:44 CEST
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Glossary · System coordination, integration and orchestration

Failover

Also known as: switchover, automatic failover

German: Failover

In high-availability systems, failover is the automatic or manual transfer of a function, service or workload from a failed or unavailable component to a redundant standby component, so that the function continues with minimal interruption.

  • System integration

In one sentence

Failover transfers a function from a failed component to a redundant standby so that operation continues with minimal interruption.

Example

When the primary SCADA server stops responding, the standby server takes over the client connections and the operators continue working after a short interruption.

How it applies

  • Engineering: Failover needs failure detection, typically via Heartbeat monitoring, a decision rule and state transfer. Define what may be lost during failover (for example data in transit) and how clients reconnect.
  • Risks: A wrong failure detection can cause “split brain,” where both units believe they are active. Designs use quorum, fencing or leases (see Lease (distributed systems)) to prevent this.
  • Maintenance: Failover paths are used rarely and can fail unnoticed. Test them periodically and after changes.
  • Documentation: Operating and service documentation should describe how failover is indicated, what operators must check afterwards and how to switch back.

Failover vs. failback

Failover moves the function to the standby. Failback moves it back to the repaired primary; it is usually a planned, manual step to avoid switching back and forth.

By knowledge.aitechdoc.world · Published September 26, 2026 · Last reviewed

Source: AI TechDoc Knowledge editorial definition, based on high-availability systems practice

Definitions follow the cited standards and specifications. Where a source is a copyrighted publication, such as an ISO, IEC or EN standard, the definition is a close paraphrase, not a verbatim quotation, so as not to infringe copyright. We recommend reading the original publication. The sections “How it applies” are editorial commentary by AI TechDoc Knowledge and are not part of any standard.

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