DreamHost’s Apache web servers are configured in process-based mode. This means that each process serves one simultaneous connection and uses a significant amount of memory for that, thus limiting concurrent user count. DreamHost offers the option to change your web server to Nginx within the panel for VPS and Dedicated Servers.
At DreamHost, Passenger only integrates with servers running Apache. If you would like to use Passenger with your application, your server must be set to use Apache instead of Nginx.
View the following article if you'd prefer to use Nginx without Passenger instead:
Changing your server
Switching to Nginx will not affect your website files. They will remain where they are and will not be touched by this change.
- Navigate to the VPS or Dedicated Dashboard page.
- Click the Configure button to the right of your server.
- Select 'nginx' from the HTTP Server drop down menu:
- Under the section Web Server Configuration is an HTTP Server dropdown:
- No web server
- Click the Save settings button at the bottom to save your changes.
- Nginx servers use async i/o and can handle large count of concurrent connections without consuming much RAM, especially when serving static files.
- Most of the time, Apache is more than sufficient but if your site is receiving very heavy traffic, you may wish to look into nginx.