I have a CentOS 6.5 server for hosting. It has sshd, httpd, mysqld, smtpd, dovecot, postfix, named working fine. but since last year I updated the server to PHP 5.4, MySQL 5.5, it starts having problems. Sometimes all services do not work except it response to ping. I added some monitoring service from 3rd party website. That website told me that my server reply 200 to httpd so it does not alarm me. All I can do is ask people in Data center to reboot it.
I want to know where is the problem. Since I cannot even use SSH to connect to server, I don't know what is the problem. Is there any way or script to find out where is the problem?