We have several Dell R210 servers running Red Hat Linux. We are seeing issues that cause the server to stick when rebooted. By stick I mean they shutdown, but stay in a state where the power is never turned off and back on. They just sit there with the diagnostics light #3 steady green. If we hold down the power button and then power them back on they boot fine. If we shut them down completely they power off without issues. We have no issues booting from a powered off state either.
The green diag light #3 being lite is supposed to mean a processor failure. We ran every diagnostic we can think of on the processors and everything checks out. Plus this happens on all 9 of our servers, which pretty much rules out processor issues since it is virtually impossible for all our processors to go bad at the same time.
One of our older Linux admins thinks it is ACPI causing the reboot to fail. Sure enough I disabled ACPI by adding acpi=off to the kernel line in grub.conf and also stopped and disabled the acpid from starting on boot. After several reboots we are having no issues.
My question is...
What is the downside of disabling ACPI? Is it even needed for a server? The server obviously never sleeps, and there is no lid to shut like on a laptop. Any input would be appreciated.