# replica set

CEFR C2 · Compound

Source: https://englishreference.com/word/replica-set
Updated: 2026-07-22

## Definition

a group of identical copies of a computer program or database running at the same time. If one copy fails, the others keep working so the service stays online.

For teachers: a group of identical instances of a software component or database maintained across multiple nodes to ensure high availability and fault tolerance. Typically managed by a controller that automatically replaces any instance that fails or becomes unresponsive.

## Examples

- The system uses a replica set to prevent data loss.
- To ensure the website stayed online during the update, the engineers configured a replica set of three database nodes.
- By maintaining a distributed replica set, the architecture achieves high availability, as the orchestrator can instantly spin up new containers to replace those that fail health checks.

## Usage notes

- Commonly used in the context of cloud computing, container orchestration, and distributed databases.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.