Q. I've upgrade my CentOS / RHEL (Red Hat Enterprise Linux) 4.7 on HP ProLiant DL580 G5 and it is showing unknown NMI errors in the logs:
Uhhuh. NMI received for unknown reason 30.
Dazed and confused, but trying to continue
Do you have a strange power saving mode enabled?Uhhuh. NMI received for unknown reason 20.
Dazed and confused, but trying to continue
Do you have a strange power saving mode enabled?
How do I fix this error?
A. This is caused when the system is hanging under load. Add any one of the following to you /boot/grub.conf file:
- Disable the NMI watchdog by adding "nmi_watchdog=0"
- Disable the high precision event timer (HPET) by adding "nohpet"
Open grub.conf, type:
vi grub.conf
Make modification to kernel line as follows:
title Red Hat Enterprise Linux AS (2.6.9-78.0.8.EL)
root (hd0,0)
kernel /vmlinuz-2.6.9-78.0.8.EL ro nohpet root=/dev/VolGroup00/LogVol00 nohpet
initrd /initrd-2.6.9-78.0.8.EL.img
Save and close the file. Reboot the server:
# reboot
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{ 3 comments… read them below or add one }
try also the “acpi=off” switch because on some cause it works better than the two ones proposed in this article
So, you recommend turning off the nmi_watchdog, that listens for hardware throwing errors that may compromise your system? Probably not smart. Just out of curiosity why would you additionally suggest changing the kernel timer as a method to avoid a hardware device throwing kill signals? BTW, this is not caused by the system hanging under load.
http://en.wikipedia.org/wiki/Non-maskable_interrupt
even wikipedia knows better
Well for one Virtual Machines cannot use NMI watchdog or HPET for that matter, so disabling will stop the errors and prevent possible problems.