Manual:$wgDBserver

Details
Database host name or ip address. Found in LocalSettings>Special:MyLanguage/LocalSettings.php|LocalSettings.php.

Tip: Use IP addresses where possible to avoid the overhead of a DNS lookup for every single connection to the wiki.

  will be faster than  

If you are using MySQL on a non-standard port you can use the "hostname:port" syntax, for example   or  . DBPort>Special:MyLanguage/Manual:$wgDBport|$wgDBport is only for PostgreSQL configuration.