Configuration management best practices for multi-site project

Hi everyone!,

I'm moving a project from single to multitise configuration (5 sites in total). But now I have to face how manage the configuration in the different sites and at the same time have a maintainable architecture for keep developing new features in the future.

My case is the following:

• Multi-site project where each site have to languages (native one + english)
• Same configuration for all sites (sections, type of contents etc..) But some differences like the language configuration or path pattern for the URLs.

According to the requirements below, my current options are:

• 1) Shared configuration folder + custom one for each site: Having 1 configuration folder for storing the shared configuration + having different specific configuration folders for each site. I think this is the best way to go, but it seems that during deployments run : drush config-import main-confing and then drush config-import custom-config --partial throws some fatal errors, and I'm not sure about if I'm doing wrong.

2) Have completely different config folders by site: Each site will have a replication of the configuration. I don't like this solution because I'll have duplicated most of my configuration and I think I'll hard to maintain.

3) Other???

What do you think about? Any of you faced this kind of situations before?

Thanks for your feedback!