[Lustre-discuss] RPMs for PAE-enabled kernels

Brian J. Murrell brian.murrell at oracle.com
Tue Dec 14 06:10:29 PST 2010


On Wed, 2010-12-08 at 13:24 +0100, Arne Brutschy wrote:
> Hi all,

Hi Arne,

> I noticed that the Lustre-provided kernel RPMs are not PAE enabled.

You didn't mention which distro or which version of kernel, but probably
that is moot anyway.

> Did
> someone do this already, and if yes where can I find them?

If you mean binary RPMs supplied by Oracle, we supply kernels that aim
to match the vendor's own kernels as much as we can and still have them
work with Lustre.

As you know, most distros have a number of kernel variants and some
distros at least as I know, have separate x86 and x86-pae kernels.  This
is likely due to the performance penalty of PAE.  Providing two x86
kernels, one with PAE and one without, gives users the choice of whether
they want/need the performance penalty of running with >4G of ram on
x86.

We don't aim to build and test and distribute every kernel variant that
the distros build as that exponentially increases the complexity (and
reduces timeliness) of our releases.  Instead we have decided to support
a single (i.e. 32 bit) x86 kernel (which for most distros, I suspect is
a non-PAE kernel due to the performance penalty) for i[3-6]86 and x86_64
kernels.

I don't know if any official policy about this is in place but I think
the general feeling about that decision is that if you really want to
use >4GB of ram, you should be using the 64-bit (i.e. x86_64)
kernel/operating system.  In fact, I think most (if not every) one uses
the x86_64 architecture and kernels on their servers as there is really
no reason (that I can think of) to use x86 there.

Cheers,
b.





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