[syslinux] IPMI serial over lan disconnects seem to trigger extlinux reboots

[Gene Cumm]

On Tue, Nov 12, 2013 at 5:20 PM, Andrew J. Schorr
<aschorr at telemetry-investments.com> wrote:
> Hi,
>
> On Tue, Nov 12, 2013 at 01:41:29PM -0800, H. Peter Anvin wrote:
>> On 11/12/2013 01:22 PM, Andrew J. Schorr wrote:
>> > I am using 4.05 because that's what's packaged in the latest Fedora
>> > release (Fedora 19 in my case).  I wonder why they are using such an
>> > old version.  I will take a look at how difficult it would be to build
>> > the latest version on Fedora.
>
> FYI, it is not so easy to package for Fedora.  I see there is an open
> bug to get this upgraded:
>
>    https://bugzilla.redhat.com/show_bug.cgi?id=869540
>
>> One possibility is that either the PXE stack or the BMC uses memory that
>> it shouldn't.  Try setting a mem= option with less memory than you
>> actually have and see if that changes things.
>
> That's an interesting idea.  I may give that a try.  Just to be clear,
> are you talking here about the kernel "mem=" boot parameter, as documented
> in kernel-parameters.txt?

Yes.  If the system has about 8192MiB RAM, I'd start by shaving it off
in about 16MiB increments or perhaps take a binary search tree pattern
approach.

> I wonder if that has negative implications for subsequent system performance...

Judicious use of that parameter should have minimal impact.  You are
right to think that it will make said RAM unavailable later but it
also affects where Syslinux loads the kernel/initrd.

> I also think I had the same troubles booting into memtest, so it may be
> a more general problem.
>
> Probably the best solution would be to replace these machines with newer
> ones, but that will be painful since they are in the field.

At least there are possibilities remaining in the interim.

-- 
-Gene