You might have seen the example.sites.php file on the sites directory when setting up your Drupal installation. This is your new friend when setting up a multisite installation on Drupal.
The the g' old way of doing this was to create symlinks for each of the site into the sites directory. Like this:
This is a typical installation of a multisite with a development, staging and live site for each site:
- Local development sites for developers (.dev domains)
- Staging server sites for staging (stagingsite1/2/3.mearra.com)
- Live server sites for, yeah, live sites (livesite1/2/3.mearra.com)
As you can see, this doesn't look nice and has it's flaws. For example, let's take PhpStorm IDE: the lovely editor is automatically assuming that you have 12 (twelve!) different sites directories that needs the indexing. That goes without saying, the indexing might take a lot of a time.
But the sites.php is the cure for this. You can just copy the example.sites.php file into sites.php or create a new file. Then add something like this in it:
$sites = array(
// Development sites
'devsite1.dev' => 'site1',
'devsite3.dev' => 'site2',
'devsite3.dev' => 'site3',
// Staging sites
'stagingsite1.mearra.com' => 'site1',
'stagingsite2.mearra.com' => 'site2',
'stagingsite3.mearra.com' => 'site3',
// Live sites
'livesite1.mearra.com' => 'site1',
'livesite2.mearra.com' => 'site2',
'livesite3.mearra.com' => 'site3',
Now your sites directory looks way more cleaner and you don't have to worry about any of the common problems caused by symlinks.
And you're all set!