Q:

background-image and sites.php

I have a multisite configuration with Drupal7, my prod site is mysite.example.mydomain.com and dev is mysitedev.example.mydomain.com I have set in sites/sites.php :
$sites = array('mysite.example.mydomain.com' => 'mysitedev.example.mydomain.com',
);

so searching for sites/mysite.example.mydomain.com would result as sites/mysite.dev. example mydomain.com, but I have a background Image Url:
background: url("/sites/mysite.example.mydomain.com/files/myimage.jpg");
if the Url is /sites/mysitedev.example.mydomain.com/files it works, otherwise with /sites/mysite.example.mydomain.com/files it don't! 
What am I missing???
Thanks.

A:

It sounds like you're confusing hostnames with file system paths.
The array mapping in sites.php is:
Hostname => Instance Folder

So taking your example, requests for http://mysite.example.mydomain.com will use the folder /sites/mysitedev.example.mydomain.com.
In that scenario, the path /sites/mysite.example.mydomain.com/files doesn't exist, so requests for files under it will return a 404. That's to be expected.
You can always add an alias/redirect via your server config, but it might be best to just use the system as it was intended.

