I ran into an issue where I had many sleeping database connections that were chewing up server capacity. It came down to a file called XMLRPC.php which is used for inter-site wordpress communication. Blocking it disables the sleep commands it was generating. 🙂
adding this to the .htaccess file dealt with it.
<Files “xmlrpc.php”>
Order Allow,Deny
deny from all
</Files>
That also breaks some trackbacks, etc…. but I can live with that.