[GTALUG] mysterious restarts

[ac]

On Tue, 14 Jun 2016 11:19:15 -0400
Alvin Starr via talk <talk at gtalug.org> wrote:
> With magical crashes I usually try to see if I can get any
> diagnostics out a serial console because once in graphical mode a
> crashing system usually has just a black screen.
> Booting and running memtest would be a good idea.
> I am assuming that the system does not have ECC memory so bad memory 
> could cause all kinds of funky problems.
> Even if it has ECC depending on the motherboard failures can cause
> reboots.
> 
the 6300 is non ecc ddr3, I had a similar problem once and it turned out to 
be a contact issue i ran the system with the mb isolated from the case
on an anti static pad - If it is a contact / power issue there will be no logs, 
reports or diagnostic info  

It could also be some other things, but my money is on contact/power/mb
as you have a reset at random times and under random load

hth

Andre


> 
> 
> On 06/14/2016 11:10 AM, D. Hugh Redelmeier via talk wrote:
> > We have a computer that started doing random and frequent restarts
> > on the weekend.  We don't know why.
> >
> > Any suggestions?
> >
> > It looks as if the power dips momentarily and the computer reboots,
> > with no message that we have observe.  But it could just as easily
> > be a crash of some other kind that leaves no trace.
> >
> > The system is an HP Compaq Pro 6300 Small Form Factor PC running
> > Fedora 20.
> >
> > The crash seems to be at different points (i.e. not one consistent
> > software activity).  The crashes don't seem correlated with heavy
> > workloads (eg. it crashed a couple of times while I was staring at
> > log files to see if there was any hint of the problem).
> >
> > Hypothesis: a Fedora 20 bug.  But the software has not been changed
> > in months.  Updates have not been appled this year.  Since the
> > behaviour has changed without the software changing, I don't think
> > that Fedora is to blame.
> >
> > Hypothesis: it might be heat-related (the room it is in gets
> > warm).  I vacuumed out the interior and defuzzed the heat sinks.
> > This did not improve the uptime.
> >
> > Hypothesis: it might be contact-related.  So I disconnected and
> > reconnected most internal connectors and reseated the memory.
> > This did not seem to improve the uptime.
> >
> > Hypothesis: it might be the power supply.  Normally, I'd swap power
> > supplies to test this hypothesis but this Small Form Factor computer
> > has a unique (and probably expensive) power supply.  I opted to move
> > the disk to a Dell OptiPlex 990 Small Form Factor computer and use
> > that.
> >
> > The Dell, with the HP's disk, seems stable.  No rebooting.  This is
> > in the same warm room, but the weather has changed.
> >
> > In the original HP box, I installed a disk that I had laying around
> > (a 60G drive from a discarded laptop), installed Ubuntu 16.04, and
> > have been running four CPU-bound processes for 24 hours.  No
> > crash.  I admit that this is in a cooler room.  The heat and power
> > load of a laptop drive is less than that of a 3.5" HDD, but I would
> > not think that that is significant.
> >
> > The computer is a couple of years old but still has a year of
> > warranty.  There are confidential files on the disk drive so I'd
> > like to narrow down the problem before calling in HP support.
> > Asking for a particular replacement part is more convenient that
> > shipping the computer back to HP.
> > ---
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