Wordpress MU Site Upgrade Bug: Your server may not be able to connect to blogs running on it
I was upgrading mu site to 2.8.4. I went to Site Admin -> Upgrade and hit Upgrade Site button. It worked for first 25 – 30 blogs and then died with message
Warning! Problem upgrading . Your server may not be able to connect to blogs running on it.
Error message: 200: Operation timed out after 3 seconds with 0 bytes received
This is what I did to fix my problem
I opened wp-admin/wpmu-upgrade-site.php and wp-includes/http.php
function &_getTransport( $args = array() ) {on line number 94 of wp-includes/http.php, wordpress tests different http request methods exist on your server during upgrade.
1st test was the culprit on my server which uses http_request method built into PHP. I guess this method was taking long time to resolve DNS and so it was timing out.
if ( true === WP_Http_ExtHttp::test($args) ) {
$working_transport['exthttp'] = new WP_Http_ExtHttp();
$blocking_transport[] = &$working_transport['exthttp'];
}I did comment out this test and let Wordpress start with next one.
if ( true === WP_Http_Curl::test($args) ) {
$working_transport['curl'] = new WP_Http_Curl();
$blocking_transport[] = &$working_transport['curl'];
}And guess what? All 150 blogs were updated in a few minutes without any problem.
If even curl does not work for you, you can comment it out and move on to the next until WP upgrade site works for you.
Good Luck!