Repointing Replica Servers for MySQL 5.7 - advice required

MySQL & MariaDB Percona Server for MySQL 5.7
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An article appeared last year that described exactly what I wished to do with some production servers, except that it covered MySQL 8.0, and I’d like to do the same on 3 servers running 5.7.37-40

https://www.percona.com/blog/repoint-replica-servers-in-mysql-percona-server-for-mysql-8-0/

I’m trying to do some gentle decommissioning, and would like to remove my “Server A” after “Server C” has become a replica of “Server B”

Currently experimenting in AWS with an equivalent setup +1 instance to run Orchestrator. I’m wondering what best suggestion would be to do this via CLI, in case Orchestrator doesn’t work for me.

My assumption is that logging needs to be turned on “Server B” and the primary details will need to be changed on “Server C”. The later is well covered, but though it seems simple, I’ve found it hard to discover a definitive description of what would be required to first switch “Server B” to be a relay and then promote to be a Primary.

Any advice gratefully received.

Mike

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Hi Michael_Shield,

For an intermediate server (i.e server B acting as relay) you need to enable both log_bin and log_slave_updates (renamed to log_replica_updates in 8.0).

Only after enabling log_slave_updates, newly incoming events from serverA will be logged to serverB binary log and can be replicated to serverC when it gets moved.

Regards

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