I'm running an apache2 server on Debian 7
Php files are handled by fcgi. After a migration of server all is working fine. But alsmost every hour the serveur doesnt answer to http requests (http client is waiting for a response for many seconds until an error 500 happens). This last for alsmost 1 minute, then all work fine.
This happens alsmost once every hour.
Didn't find any reason, any cronjob that would match.
But in the log i have 3 related kinds of errors :
mod_fcgid: can't apply process slot for /var/www/user/wrapper Premature end of script headers: script.php mod_fcgid: read data timeout in 40 seconds
Also, memory usage, and cpu usage are normal during the minute the server doesnt answer and put that in the logs.