Load balancer
A load balancer distributes connections or requests across several destinations. Distribution rules, state handling and failure checks determine its behaviour.
What is a load balancer?
A load balancer distributes incoming connections or requests across several servers or application instances. NGINX explains this for HTTP traffic and different distribution methods. The destinations selected depend on configuration. Load distribution does not automatically mean identical numbers of business operations per instance.
Example: running several portal instances
A fictional team runs several instances of the same portal. The load balancer chooses a destination for a request. The team must establish where sessions, uploaded files and shared data reside so that switching destinations does not produce conflicting views.
It also defines how unusable destinations are detected and removed from distribution. A server being reachable does not confirm that every business workflow works.
The load balancer itself and shared services can also fail or become bottlenecks. Several portal instances alone therefore do not prove high availability; the intended behaviour during failure must be checked.
Sources
Related terms
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- Capacity planningCapacity planning connects expected usage with performance targets and resources. Measurements and load tests check assumptions, which are updated over time.
- Return-PathReturn-Path records the SMTP reverse path in a header. It explains the technical route for error reports, not a person’s identity.
- Envelope-FromEnvelope-From identifies the SMTP sender for transport and error feedback. It must be distinguished from the visible sender address.
- DMARC aggregate reportA DMARC aggregate report summarises a reporting mail system’s domain checks over a period. It helps examine sending sources and misconfigurations.
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