64bit/Dual Core Issues and Recommendations?

[Shawn Wallbridge]

On 18-Sep-05, at 9:18 PM, Bill Binko wrote:

> I'd like to thank everyone for the feedback on this.  I must say it's
> mixed :-(
>
> I am in an interesting situation, however: while my hardware needs  
> will
> (hopefuly) grow to be considerable, my initial risk (in terms of  
> real $$)
> is fairly low.  Even an occasional down time would be acceptable until
> about January, when I expect to ramp up usage.
>
> Therefore, I'm considering the following strategy.  I think it will
> provide the highest potential reward, while leaving me a fall-back
> position without looking too much investment.
>
> I plan on going ahead with a dual 64-bit Opteron system.  I haven't
> decided on dual-core or not.  I also have considered starting with a
> single dual-core CPU and adding another near the end of my test cycle.
> That might save me cash if I decide I have to scrap this and go to  
> a more
> conventional system -- I am leaning toward just getting two CPUs up  
> front.

I would say that is an excellent strategy. I would stick with single  
core for now, just on a price/performance basis. As long as your  
motherboard supports dual cores, you have a potential upgrade path  
that is 'relatively' painless if you need it. Right now the costs of  
Dual Core processors is about 3-4x the price of single cores (from  
the places I have looked).

>
> From everything I have heard, I can run 32-bit Linux on these  
> without any
> problems from any of the core open source GIS apps.  (Please  
> correct me if
> I'm wrong on that impression).
>
> I will start with a 64-bit Linux, and rebuild my core apps 64-bit.   
> That
> would give me from my purchase date (probably about 2 weeks out)   
> through
> my development (until Nov 10) and through my testing cycles  
> (through Jan
> 1) to find and fix as many 64-bit issues as I can.  If I find it's
> unstable for my purposes, I will fall back to 32-bit Linux and 32-bit
> apps.
>
> Assuming I take this route, I would be happy to provide SSH access  
> to all
> of the core developers of the systems I'm using (GDAL, Mapserver,  
> PostGIS,
> etc.) if they would like to test on that platform (hint, hint, Frank).
>
> I am making the assumption that all of the core apps are 80-90%  
> working on
> 64-bit systems.  I'm willing to be guinea pig and bug-hunter for the
> remaining 10-20% given the situation I'm in and the potential  
> benefit of
> running 64-bit (and much faster from the annecdotal feedback I've  
> gotten).
>
> Again, thanks for the input,
>
> Bill

I wish I had an Opteron I could give the developers access to right  
now. While my hardware will all be 64bit, it will be UltraSPARC and  
MIPS based ;-) But they are welcome to access to those.

Worst case, you should have no problems running 32bit apps on it. We  
are running straight 32bit on our 120 Dual Opteron's without any  
problems.

shawn