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?

  • Does your hosting provider offer out-of-band management? (Remote console?) If not, all you can do is ask they reboot. – Aaron Copley Mar 23 '15 at 15:51

The first step would be looking at all log files, in particular /var/log/syslog.

Without any information my guess would be that it is an out-of-memory condition. Any service (including ssh) would stop, ping is pretty much the only service still working because it is directly handled by the kernel.

  • I don't have syslog in the log folder. I only have boot.log, dmesg, maillog, mcelog, messages, secure, and some other files. which one should I look into? If it is the out-of-memory problem, how can I find which service used all the RAM? – hatted Mar 24 '15 at 1:43
  • I found the Mem used very fast. Mem: 24685044k total, 23025540k used, 1659504k free, 516436k buffers Swap: 10223608k total, 152k used, 10223456k free, 17774752k cached – hatted Mar 24 '15 at 2:09
  • but free shows i used only 4G ram.# free -m total used free shared buffers cached Mem: 24106 22523 1582 0 505 17411 -/+ buffers/cache: 4607 19498 Swap: 9983 0 9983 – hatted Mar 24 '15 at 2:13

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.