What is DB Replication?

Anubhav Sharma 331 26 Jan 2026

Anubhav Sharma

Student

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1 Answers

Anubhav Sharma 26 Jan 2026

DB Replication (Database Replication) is the process of copying data from one database to one or more other databases so that all of them stay in sync.

In simple terms:
the same data exists in multiple databases.

How DB Replication Works

One database acts as the Primary (Master)
Other databases act as Replicas (Slaves)
Changes (INSERT, UPDATE, DELETE) on the primary are copied to replicas

Why DB Replication Is Used

High availability – database still works if one server fails
Read scaling – read queries can go to replicas
Disaster recovery – backup databases are ready
Performance improvement – reduces load on the main DB

Types of DB Replication

Synchronous – data is written to all replicas immediately
Asynchronous – replicas update after a short delay (most common)
Semi-synchronous – hybrid approach

Example

Writes → Primary DB
Reads → Replica DBs

Used heavily in MySQL, PostgreSQL, SQL Server, MongoDB, and cloud databases.

DB Replication vs Sharding

Replication = same data copied
Sharding = data split into parts

In one line:
DB Replication keeps multiple databases in sync to improve availability, performance, and reliability.

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