Thanks Andreas! Actually googling I found another thread from you in 2003 with similar issue. Below my comments to your answer(s)

...

How much RAM support the SuSE 9.2 Professional kernels 2.6.xx , as maximum, over an AMD 64-bits installation?

256 GB - if you have such a machine tell me, we haven't tested it ourselves ;-)

So, please, how do you know that number? :-) Is something to be read from the kernel?

...

Is there any known issue / trick to get all of the RAM available on systems with 8 GB or more ?

The BIOS has to do setup this correctly.

The initial check of RAM seems to be OK. (bios) 8192 MB OK. I don't find any configurable option in the bios about RAM above 4 GB. (except something about MTRR Mapping, I've no idea what it is, but I've tried both enable/disable and didn't work. The bios version is quite new (Tyan S8882 , AMIBIOS Version 08.00.10, Built Date: 06/28/04 ) and the manual says that up to 16 GB are supported. So there must be something with the kernel defaults, which occurrs above 4 GB. Still more data: If I pass mem=3072m as option, the SuSE installer & rescue system boot correctly. If I pass mem=4096m as option, they not. So ... why are you sure that this (I quote you from 2003 thread:) is " a bios problem, *not a kernel* problem ..." cheers, Juan Pablo ps.: I'm somehow sad that everyday more Red logos and less Green are to be seen in the SuSE boxes, and in the web site. The last thing which makes me sad... www.suse.de does drive you now to www.novell.com. I am in Germany, why should I see a page from the us? So ist das Leben... ______________________________________________ please use : Fachbereich fuer Physik, Universitaet Konstanz, Universitaetsstr.10, Fach M 686, 78457 Konstanz, Germany Phone: +49 7531 88 3825 ______________________________________________

Hi there, It was the USB host controller what caused the problem of SuSE 9.2 not booting. Once I have disabled the USB host controller from the BIOS then the problem was gone. It is somehow annoying, anyway these Opterons were thought to be not workstations but computing nodes. What it is really strange is that this "interference" between the USB and the RAM occurs only below 4GB. Because as I said before, the system also boots with up to 3 GB (passed as mem=3072m at booting time) while USB is enabled. Just as more detail, I have installed the kernel 2.6.8-24 with smp. Opteron 248, 2.2 GHz, 8 GB RAM. Motherboard Tyan S2882 Thunder K8S PRO. Suse 9.2 seems to be working ok now, without the USB. ;-P Thanks a lot, Juan Pablo Zagorodny On Friday 10 December 2004 21:55, you wrote:

Juan Pablo Zagorodny writes:

...

Thanks Andreas! Actually googling I found another thread from you in 2003 with similar issue.

Below my comments to your answer(s)

...

...

How much RAM support the SuSE 9.2 Professional kernels 2.6.xx , as maximum, over an AMD 64-bits installation?

256 GB - if you have such a machine tell me, we haven't tested it ourselves ;-)

So, please, how do you know that number? :-) Is something to be read from the kernel?

This is the limit of the kernel implementation - with three levels of page tables you can address 256 GB of RAM (or 512 GB of total virtual memory). Andi is working on 4 levels of page tables to increase this.

...

...

...

Is there any known issue / trick to get all of the RAM available on systems with 8 GB or more ?

The BIOS has to do setup this correctly.

The initial check of RAM seems to be OK.

(bios) 8192 MB OK.

You have a whole in the 4 GB region to map cards that have 32-bit adresses. There are two solutions for this: - just map it over ram making the ram unavailable - remap the ram

...

I don't find any configurable option in the bios about RAM above 4 GB. (except something about MTRR Mapping, I've no idea what it is, but I've tried both enable/disable and didn't work.

The bios version is quite new (Tyan S8882 , AMIBIOS Version 08.00.10, Built Date: 06/28/04 ) and the manual says that up to 16 GB are supported.

So there must be something with the kernel defaults, which occurrs above 4 GB.

Still more data: If I pass mem=3072m as option, the SuSE installer & rescue system boot correctly. If I pass mem=4096m as option, they not.

So ... why are you sure that this (I quote you from 2003 thread:) is " a bios problem, *not a kernel* problem ..."

Always ;-).

Please send more details - and wait for Andi to answer when he's back From his vacation...

Andreas

-- ______________________________________________ please use : Fachbereich fuer Physik, Universitaet Konstanz, Universitaetsstr.10, Fach M 686, 78457 Konstanz, Germany Phone: +49 7531 88 3825 ______________________________________________

On Fri, Dec 10, 2004 at 09:55:23PM +0100, Andreas Jaeger wrote:

Juan Pablo Zagorodny writes:

...

Thanks Andreas! Actually googling I found another thread from you in 2003 with similar issue.

Below my comments to your answer(s)

...

...

How much RAM support the SuSE 9.2 Professional kernels 2.6.xx , as maximum, over an AMD 64-bits installation?

...

256 GB - if you have such a machine tell me, we haven't tested it ourselves ;-)

So, please, how do you know that number? :-) Is something to be read from the kernel?

This is the limit of the kernel implementation - with three levels of page tables you can address 256 GB of RAM (or 512 GB of total virtual memory). Andi is working on 4 levels of page tables to increase this.

Actually it's a bit more complicated. The current kernels support upto 512GB GB virtual address space per process (in practice it's a bit less because of fragmentation so let's say 400GB usable without special tuning) But over multiple processes you can have much more. The current physical limit of the x86-64 architecture is 40bits on AMD (1TB) and 36bits on Intel EM64T (64GB). The kernel supports more than that in theory. A future version of the x86-64 kernel will extend the 512GB limit per process to ~127TB. -Andi