8GB RAM: PAE or not PAE?

[Martin Cracauer]

err wrote on Wed, Aug 29, 2007 at 05:42:36PM +0200: 
> Hi
> 
> I have an HP DL380 quad core with 8GB of RAM and SAS disks in RAID, with freebsd 6 STABLE on it. 
> 
> Everything works fine, except for the RAM addressing problem: freebsd sees only 4GB.
> I know it have been discussed, but it could be a problem to me for running a 64bit compiled system; what is the stability of a kernel compiled with the PAE option?
> 
> I've a kernel with no modules, and before trying PAE I would know for other people experiences...
> In particular I'm interested in the behavior of ciss, bce, em and usb stuff, and application like Perl, Ruby, PHP 5, MySQL server, heavy MAWK and bzip2 load.

Usb? Ugh.

But last time I ran i386+PAE was 6.2-beta and it ran fine with 8 GB
and 8 processors, well enough to complete a complex benchmark suite.
I wouldn't know about USB and other non-primary drivers.

You should also be able to run a 100% 32 bit userland with a 64 bit
kernel.  I'll have to do that next weekend or whenever I find time,
for other reasons.

> Also, if I boot a PAE kernel, in order to have all my RAM available, I have to set the hw.physmem variable to 8G ?

No.

Martin
-- 
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
Martin Cracauer <cracauer at cons.org>   http://www.cons.org/cracauer/
FreeBSD - where you want to go, today.      http://www.freebsd.org/