I have 2 seperate MySQL 8 instances running on Ubuntu 20.04. One starts via systemd "normaly" and the other one I can invoke by using:

mysqld_safe --defaults-file=/home/username/mysqld_replica.cnf &

Now that everything is running I was investigating on how to start the second instance on boot. I discovered mysqld_mulit and wonder now if:

  1. What are the advantages of mysqld_multi over seperate config files?
  2. How I can start the second instance on boot if not using mysqld_multi
  • why multiple instances on a server at all? there are only s much resources that have to be shared.
    – nbk
    Jul 11, 2021 at 15:17
  • I want to seperate a replica instance from a staging instance.
    – merlin
    Jul 11, 2021 at 16:54
  • I thought that _multi was no longer supported and Docker was the preferred way?
    – Rick James
    Jul 14, 2021 at 21:04

1 Answer 1


Some advantages of using mysqld_multi:

  • You can start, stop, or restart all the instances with one command.
  • You can use one config file, keeping the config options common to all instances in a [mysqld] section, and only the instance-specific options in the instance section.

If you don't use mysqld_multi, you would need to create your own systemd entry for your second instance.

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