How to use tmpfs with Docker Compose and MySQL

I recently needed to run a MySQL database on a tmpfs (RAM disk) filesystem with docker compose, it allowed me to have pretty good tests performance in my client’s Rails application. It can be achieved quite easily with this config:

This uses RAM to store data in memory, so it’s not recommended when files are not cleaned up and might grow bigger than Your machine’s RAM

version: '3'
services:
  mysqldb:
    image: mysql:5.7
    restart: unless-stopped
    environment:
      - MYSQL_ALLOW_EMPTY_PASSWORD=true
    ports:
      - "3306:3306"
    tmpfs:
      - /var/lib/mysql

This can also be used in many different scenarios like file processing microservices that don’t save anything, or boosting Your application’s tmp directory RAM disk.

That's it for this post, thanks for reading!