8GB RAM: PAE or not PAE?

[Josef Grosch]

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.


Josef

-- 
FreeBSD 6.2         |
Josef Grosch        | Listen, strange women lying in ponds distributing
jgrosch at juniper.net | swords is no basis for a system of government.