[CentOS] System hangs silently

Fong Vang wrote:
> I have a total of 20 CentOS 4.1 systems running on fairly new
> hardware.  About 6 of them are experiencing strange hangs without any
> indication -- nothing in /var/log/messages nor on the console --
> sometime within 10-30 minutes after a reboot.  The systems still
> responds to ping but you can't ssh to it.  At the console, you could
> type "root" at the user prompt but it hangs immediately after hitting
> enter.
> 
> Memory scan of all systems show no error.
> 
> Any idea how to troubleshoot this problem.  The system's not
> responsive to do any troubleshooting and nothing abnormal is in the
> log.
> 
> We running htis kernel: kernel-smp-2.6.9-11.EL.i686.rpm.

Have you tried disabling hyperthreading? I had suffered this problem
when we started buying Intel Xeon's, disabling HT'ing seemed to fix the
problem for me.

Dean