topic Re: Hung httpd process in Operating System - Linux

Hung httpd process

Sivasingam Santhakumar — Sun, 13 Nov 2005 19:02:39 GMT

Dear Admins,

I have a starnge situation that from time to time httpd process hungs and even root can't kill it only reboot will clear it. OS Redhat AS2.1 with Apache 1.3.1. Any suggestions?

Thanks.

Re: Hung httpd process

RAC_1 — Sun, 13 Nov 2005 22:47:08 GMT

A hung process is dead process. You can not kill it even with kill -9. The only optio is reboot if you have to.

But find out why it hangs. You can start with running tusc against it and see what system call it hangs on.

tusc -vfp "httpd_start_command"

Re: Hung httpd process

Steven E. Protter — Mon, 14 Nov 2005 05:57:29 GMT

If its PPID is 1 and kill -9 does not work:

service httpd restart

If that does not work, restart the system.

SEP

Re: Hung httpd process

Ivan Ferreira — Mon, 14 Nov 2005 06:13:48 GMT

If you can, you should upgrade your apache version.

Also, you should investigate why the process hungs. Verify the log files.

Are there any indications?

Re: Hung httpd process

Sivasingam Santhakumar — Mon, 14 Nov 2005 06:28:46 GMT

Is tusc a hp-ux command? My server is RedHatAS 2.1

Re: Hung httpd process

NiCK_76 — Mon, 14 Nov 2005 11:01:36 GMT

Hi Sivasingam ,

I ever encounter same symptom. I found the root cause is I/O system problem. Maybe you too.

If it is. I suggest you upgrade I/O controller driver and linux kernel to have a try.

NiCK

Re: Hung httpd process

Ralf Hildebrandt — Mon, 14 Nov 2005 17:47:17 GMT

Try "strace -p pid_of_the_process" to see what it does and why it hangs. Also check to logs to see what was logged before the condition you observe.

Re: Hung httpd process

Sivasingam Santhakumar — Wed, 16 Nov 2005 00:15:30 GMT

Thanks for the input, the logs and other tolls doesn't tell much. I will continue my research.

Re: Hung httpd process

Sivasingam Santhakumar — Wed, 16 Nov 2005 00:16:09 GMT

When I was looking deep into it I found (with lsof) that rotate logs delete the logs files while a processor looking at it. Does it make that processor hang?