system hangs

[Chakravarthi]

All,

Machines reboots after giving this error
kernel: Uhhuh. NMI received for unknown reason 21.

kernel: Dazed and confused, but trying to continue

kernel: Do you have a strange power saving mode enabled?

what needs to be checked??

--chakri

[Ivan Ferreira]

Try updating your kernel fist.

Responses received on other forums:

I saw messages very similar to this on a PE750, although my system did
not power down - it just panicked. I traced the problem to a bad
third-party DIMM I had used to upgrade the memory on the system.

Run memtest86+ on the machine for at least 24 hours. In my case that
would cause the system to NMI within 10-13 hours. If memtest86+ runs
for 24 hours without problems, I would be reasonably confident that
the issue is not your memory.

========================================

About a year ago one of our 1750s reported the same error. After a
power cycle it came back up fine for about 2 days and then crashed
again. After another power cycle it crashed after a few hours. Neither
reseating or replacing the ram helped in that case, and after a week of
being shelved it wouldn't even complete the boot process when it was
tried again. Ultimately replacing the motherboard fixed the issue, but
I recall that CPUs were also a possible cause of this error.
If you have a spare system, I'd pull this one and try reseating the
ram, replacing the ram, replacing the motherboard, replacing the CPUs in
that order - and letting the system run under moderate load for a few
days at each step to see if it's resolved. If you don't have a spare
system but do have a support contract I'd replace the motherboard and
ram at the same time, and the CPUs if it crashes again after that
replacement.

=====================================

[Gopi Sekar]

reasons could be memory problem or power savings mode.

Try these:

*check memory, use memtest86 tool to do that

* disable power saving feature in BIOS, or better when the kernel boots up pass on the kernel parameter acpi=off it will turn off kernel power modules

Let us know the result
Hope this helps,
Gopi