This directory is for configuring multisite installations of Backdrop CMS.

Backdrop CMS supports running multiple sites with different domain names from the same codebase. For example you could point example-a.com and example-b.com at the same server and same directory and Backdrop CMS could run both sites. This is useful for sites that have extremely similar or even identical configuration and features. If you have several sites running Backdrop CMS but they have different modules installed, you should probably use entirely separate installations of Backdrop CMS in different directories.

If you don't plan on using the multisite functionality of Backdrop CMS (most don't), you can safely delete the entire /sites directory.

If you DO plan on using the multisite functionality, you will need to do the following:

• Configure the sites.php file (see below)
• Create a new sub-directory of /sites with the name as specified in sites.php (e.g. /sites/example-a)
• Copy the default settings.php file (i.e. /settings.php) into the new sub-directory (i.e. /sites/example-a/settings.php).

To enable Backdrop CMS's multisite functionality, edit the sites.php file in this directory. The $sites variable can be used to make Backdrop CMS use different database settings, modules, layouts, and themes based on the URL of the site.

For example if you wanted to have example-a.com and example-b.com running off the same Backdrop CMS installation, you would specify the following values in the $sites array:

$sites['example-a.com'] = 'example-a';
$sites['example-b.com'] = 'example-b';

Then you could place site-specific settings in sites/example-a/settings.php, modules in sites/example-a/modules, layouts in sites/example-a/layouts, and themes in sites/example-a/themes. The same could be done for the example-b sites. Both sites will share the modules, layouts, and themes that are provided by Backdrop CMS core, as well as the modules, layouts, and themes located in the root directory. Each site will always have a different database, configuration, and files directory.

If developing on a multisite locally, you may also want to specify aliases for those same directories so that Site A and Site B can be accessed separately on your localhost or development environment:

$sites['example-a.localhost'] = 'example-a';
$sites['example-b.localhost'] = 'example-b';

$sites['dev.example-a.com'] = 'example-a';
$sites['dev.example-b.com'] = 'example-b';

Besides the simple examples based only on domain name, you can also specify site directories based on path and port, with the format $sites['<port><domain><directory>'] = 'directory';. Some advanced examples:

URL: http://localhost:8080/example

$sites['8080.localhost.example'] = 'example';

URL: http://www.example.com:8080/mysite/test/

$sites['8080.www.example.com.mysite.test'] = 'example';