i386 with PAE or AMD64 on PowerEdge with 4G RAM

[Martin Turgeon]

2007/6/18, Jeremy Chadwick <koitsu at freebsd.org>:
>
> On Mon, Jun 18, 2007 at 01:03:44PM -0400, Martin Turgeon wrote:
> >  I just receive 2 PowerEdge servers (a 1950 and a 860) both with 4G of
> RAM. I
> >  installed FreeBSD 6.2 Release i386 on both of them. Unfortunately, only
> 3,5G
> >  is recognized on the 860 and 3,3G on the 1950.
> >  dmesg on 860:
> >  real memory  = 3757834240 (3583 MB)
> >  avail memory = 3678318592 (3507 MB)
> >
> >  I am facing a difficult decision. Should I use i386 with PAE enabled in
> the
> >  kernel (I read a lot of warnings using it) or should I go with AMD64?
> Which
> >  branch should I follow?
>
> Based on what I've read from some of the porters and miscellaneous
> others, generally-speaking there's too many issues with amd64 (in the
> sense of 32-bit vs. 64-bit compatibility -- not the fault of the kernel
> or otherwise) to consider it worth switching to.
>
> I personally don't run 64-bit OSes because most developers still use
> 32-bit machines and don't have a way to develop/test in 64-bit
> environments.
>
> That said, I'd recommend you stick with i386 + PAE, simply for
> guaranteed application compatibility.


My setup is fairly standard (as I described), should I expect problem with
64 bit version of these programs?


You'll lose the amount of RAM you're seeing due to PAE addressing for
> PCI address space.  I can dig you up a usage map (broken down by how
> much is taken up by each portion; PCI, ACPI, etc.) if you want one.
> It's for SuperMicro systems, but the general idea applies to most
> everything.


I'm not sure to understand what you mean by that. Are you saying that PAE
will eat the 500M that should be available?

--
> | Jeremy Chadwick                                    jdc at parodius.com |
> | Parodius Networking                           http://www.parodius.com/ |
> | UNIX Systems Administrator                      Mountain View, CA, USA |
> | Making life hard for others since 1977.                  PGP: 4BD6C0CB |
>
>