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Configuration·MySQL

MySQL Replication Prerequisites

Three servers, three unique ids, GTID on everywhere and one account with exactly one privilege. Every replication problem later is easier when this part is exactly right.

Replication Guide 26 of 45 Intermediate

GTID replication is the modern default approach. File-and-position replication still works and is what most older documentation describes; auto-positioning removes the step where you copy coordinates by hand and get them wrong.

db-a01 is the source. db-b01 and db-c01 become replicas - two, because a single replica cannot show what a second one does differently.
Server NameIP AddressOSRolesCPURAMHDD
db-a01192.168.0.81Ubuntu 26.04 LTSPrimary / Source / Replica Set Member 12 Core4 GB50 GB
db-b01192.168.0.82Ubuntu 26.04 LTSStandby / Replica / Replica Set Member 22 Core4 GB50 GB
db-c01192.168.0.83Ubuntu 26.04 LTSReplica Set Member 3 / Cascading and Delayed Replica2 Core4 GB50 GB

This guide includes

Use this before configuring any replication at all. This matters because three things have to be true on every server first - a unique id, GTID enabled, and one account with exactly one privilege - and getting them wrong only shows up much later.

Before you start

  1. Give every server a unique identity

  2. Validate, then restart all three

  3. Confirm the topology agrees

  4. Create the replication account

Official sources

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