[Beowulf] Changing BIOS settings on nodes

Honest Guvnor honestguvnor at googlemail.com
Fri Sep 28 01:17:13 PDT 2007

On 9/28/07, Steffen Grunewald <steffen.grunewald at aei.mpg.de> wrote:
> Even a very simplistic VGA should be standard - how would you handle a
> very early disk failure, or any other emergency of there's no way to
> read out the status of the system that's not running the OS yet?

We use a serial console to look at problems after the OS has started
booting but if we have problems before this at the BIOS stage then we
take the node out and put a video card in it and attach mouse,
keyboard and monitor. We have needed to do this with only 3 nodes in a
few years and so is not much of an issue. We could do this to address
our current problem but nobody has volunteered to do it for all the

A computational cluster with a limited budget is something of a
compromise. When it was constructed a few years ago we established
that processor type was important, processor speed did not matter much
but support for the highest speed main memory access was vital for
working with our large matrices. This limited our choice of
motherboards to some of the upper end desktop boards which did not
tend to have on board video. Server motherboards were far too
expensive to make sense.

We looked for a batch of old video cards being sold off but nobody we
approached had any in stock and since we had a workable fallback they
never got bought. With hindsight we should have enabled PXE when we
reassembled most of the nodes. Our supplier misassembled 2/3rds of the
machines possibly because the absence of a video card encouraged them
to skip even minimal testing.

> BTW, PXE booting would have to be enabled in two places: in the firmware
> part of the ethernet adapter itself, *and* in the boot order. I'm not
> aware of any way to do the first step without manual intervention (CTRL-S
> or CTRL-B) even if the second step was successful. (Some of us have asked
> the board/BIOS maker for a customized version, with PXE booting enabled.)

Thanks for this, I did not realise that both settings were not in the
BIOS and so it tells me to stop looking for solutions in this

> > This is where the Crash Cart comes into play. You know, the one with the
> >  tools, crimper, maybe some spare fans, etc. Usually a monitor and
> > keyboard as well.
> If there's nothing to connect to you'd be lost with even that.

But we have 2 video cards on our "cart" (which is actually a table in
the corner of the room).

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