[CentOS] Strange reboots

Thu Apr 10 22:44:59 UTC 2008
Benjamin Karhan <simon at pop.psu.edu>

A little birdy told me that Linux said:

] I have a CentOS 5.0 running as a web server.
] # uname -a
] Linux hostnamehidden.net 2.6.18-53.1.14.el5 #1 SMP Wed Mar 5 11:37:38
] EST 2008 x86_64 x86_64 x86_64 GNU/Linux
] Every 59 minutes (maybe every hour) it reboots without any logs,
] without any traces and unfortunately with breaking software raid.
] After reboot dmesg does not have any strange entries.
] I double-checked crons, any strange services, nothing suspicious.
] I did "yum update" recently.
] I went to Datacenter and waited before the monitor but during reboot I
] did not see anything strange. I guess reboot is cold reboot.
] I changed all system and cpu fans. Upgraded system powersupply with a
] more powerful one. Placed server infront of air-conditioner.
] Do you have any idea?

i have only recently started to believe CentOS 5 (not CentOS' fault
  at all, but really RHEL 5) is stable on a large enough scope of
  hardware to begin moving from CentOS 4 (which has been rock solid
  for my job's organization and my home use for years)...

the issue you describe was one of the many symptoms that would
  manifest on some systems running 5... especially early on...
  as a suggestion, try disabling (really not installing) the X-server
  and see if the problem doesn't vanish...
  although i wouldn't consider that an acceptable "solution" for
  my own long term use (and thus the hesitance to move from 4 to 5)
  that WAS often a culprit in "periodic spontaneous crash/reboots"...

i've found the simplest way to test this without massive software
  removal or reinstallation is to change the initdefault in
  /etc/inittab to "3"...
  and then to remove (or rename) /etc/X11/xorg.conf (to prevent the
  X-server from running during the boot notification sequence and
  possibly hanging at exit, thus preventing even console logins)

this really only helps you if you have X11 installed/enabled to begin with...

B. Karhan
simon at pop.psu.edu
PRI/SSRI Unix Administrator