8GB RAM: PAE or not PAE?

[John Baldwin]

On Wednesday 29 August 2007 04:51:10 pm Josef Grosch wrote:
> On Wed, Aug 29, 2007 at 05:42:36PM +0200, err wrote:
> > 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.
> > 
> > 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 ?
> > 
> > Thanks
> > --
> > Emmanuel Richiardone
> 
> 
> Based on my experience with PAE I would say, don't. I found PAE to be very
> brittle. Not all the drivers work well with PAE. Most recent Intel
> processors understand 64bit. I have several machines in our datacenter
> which are Intel 5160 running amd64.

4.x + PAE is rather questionable, but 6.x + PAE is quite stable.

-- 
John Baldwin