Re: server upgrade question
On Thu, Dec 11, 2008 at 11:33:09PM -0500, Mag Gam wrote:
> At my university we have 10 servers. Each server has 8 cores with 32
> GIG of memory running Debian 4.0. We have to give these servers to a
> different department, and our Dean would like to consiladate 10
> servers into 5 servers. The new server will have 16 cores with 64 GIG
> of memory. Basically a 2:1 type of deal.
>
> Since we are doing a 2:1, should we expect 2:1 performance? For
> instance, most of our applications are heavy compute and memory
> intensive applications. Would they run at the same speed, better, or
> worse with this new setup? My guess is that same?
>
> Oh, yeah will be running 4.0 :-)
Huh? 10 servers * 8 cores * 32GB makes 80 cores and 320GB. 5 servers *
16 cores * 64GB makes 80 cores and 320GB. Even assuming that all the
cores operate at the same speed (which depends, for example, on how
many cores per CPU there are), you'll lose a lot of performance
because the same amount of cores and memory will have to share 1/2 the
amount of servers. That might cut your performance in half.
The other way round: Imagine you have two computers with one CPU, one
core each. You have 16GB of memory in each. Now you replace the two
computers with one that has one dual core CPU and 32GB of memory. It
will be slower because instead of having "dedicated" resources for
each core, you now have several cores sharing the resources. If you
replace them with a computer that has two single core CPUs on the
board, it will also be slower because two CPUs share the resources.
Other than that, the performance can better or worse, there are too
many other factors that influence it. You'd have to do some benchmarks
to tell.
--
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