Help with silent reboot of 10.3-stable system

[Rodney W. Grimes]

> Over the past month or so my network fileserver system (NFS support for my
> entire, small, network) has begun silently rebooting itself. Here is the uname
> -a output:
> 
> FreeBSD vader.immure.com 10.3-STABLE FreeBSD 10.3-STABLE #15 r313997: Mon Feb 20 14:40:00 CST 2017     bob at vader.immure.com:/usr/obj/usr/src/sys/GENERIC  amd64
> 
> At first I suspected that it might be the power supply as it was a couple of
> years old so I replaced that. Unfortunately, it has begun doing it again (had
> a couple of weeks respite) so now my suspicions seem to have been incorrect.
> 
> I was hoping that someone might be able to give me some clues on what I can do
> to reveal the problem. Are there any general debug settings for the kernel (or
> elsewhere) that would maybe give an indication of why it is being rebooted
> (assuming it's a software problem)?
> 
> Thanks for any suggestions you may have!

Given that you have already suspected hardware I'll continue down that
road and leave the software road for others to persue.

Was it rebooting more often than every couple of weeks?  It sounds
as if a power supply swap fixed the problem for a short period,
but it has come back.  If that is true my suspecion would be
bad primary side filter caps in the cpu vrm on the motherboard.

Your replacment powersupply has nice new filter caps, if you
did put in a new power supply, if you put in a used one, go
get a brand now one.  PC power supplies are junk when it comes
to there output filter stages, and I dont care how expenive
of a supply you buy.  No one engineers a life of more than
3 years into them anymore.   Anyway, changing this cleaned
up the primary side of the vrm for a while, but since those
capacitors are degrading this let them get even worse as
when caps start leaking they make heat and the hotter they
get the more they leak and it spirals into a cook off that
usually ends in the cap leaking blank gunk out the top,
or in some cases out the bottom.

Please look very carefully at the MB CPU filter caps, google can help you
if your now a hardware type to find what your looking for. 
Google: motherboard bad caps

How old is the is motherboard?  Anything more than 2 years old can easily
have degraded caps.   Unless it is using solid polymer types, then I give
them 3 or 4 years.   Again nothing is engineered to last much beyond
warranty.  Any life beyond warranty is not by design, but simply the
accidental nature of things often work better than speced.

> Bob
> -- 
> Bob Willcox    | If a program is useful, it will be changed.
> bob at immure.com |
> Austin, TX     |
> _______________________________________________
> freebsd-hackers at freebsd.org mailing list
> https://lists.freebsd.org/mailman/listinfo/freebsd-hackers
> To unsubscribe, send any mail to "freebsd-hackers-unsubscribe at freebsd.org"

-- 
Rod Grimes                                                 rgrimes at freebsd.org