With mem per CPU, Opterons scale very well in most cases (as long as you
have many processes). The lower memory latency helps too.
Is it likely for you to be network bandwidth limited - e.g. maxing out your
NICs or NIC I/O capacity? I doubt it, but if you are actually getting close
then things get a bit harder...
BTW in most Opteron configs, a lot of the major I/O goes through via one CPU.
Check this out:
http://www.aceshardware.com/read.jsp?id=60000277
The benchmarks could be interesting too.
At 05:06 PM 3/8/2004 -0700, Steve Wolfe wrote:
> The main question in my mind is whether a 4-way Opteron is going to
>give me enough of a performance benefit over a 2-way Opteron to make the
>extra $10k worth it. My first guess was that it would, as going from 2
>Opterons to 4 will give you twice the potential memory bandwidth.
>However, as PostgreSQL pulls heavily from the global buffers, I may not be
>able to utilize all of that potential bandwidth.
>
> If anyone has done tests with PostgreSQL on 2- vs. 4-way machines under
>heavy load (many simultaneous connections), I would greatly appreciate
>hearing about the results.
>
>Steve Wolfe