Failed connection or timeout to remote MySQL server takes web sites offline

[Paul Field]

I have a Linux web server that contains a number of websites in PHP.

A few of the sites do queries to a remove MySQL server, some of the sites use local MySQL, and most don't use any MySQL at all.

Whenever the remote MySQL server can't be reached, it quickly stops all the sites on the server from responding.

Is there any config to stop the other sites from being dragged down by the sites trying to do the remote queries?

I'm assuming this is all because there is a query queue somewhere on the local server that fills up and something dies.

When the remote MySQL server comes back online, everything catches up in a few minutes and all the sites come back online too.

Thanks