[Asterisk-Users] Best performing CPU for G.729 codec?

[Chris Albertson]

--- Steven Critchfield <critch at basesys.com> wrote:
> On Wed, 2003-10-22 at 09:40, Chris Ziomkowski wrote:
> > Hi everyone,
> > 
> > I need to build a machine capable of running at least 30 G.729
> channels 
> > with lots of room to spare because it will be doing some other CPU 
> > intensive tasks also.

I hate to say it, but jumpping off into a 100 channel PBX is not
the way to go with Asterisk.  Build a 1x1 PBX first on an old 
Pentium 500. get this to work then try adding SIP phones then
add some other features.  After you've spent some time you will
not need to ask the above.  In fact I'd say if you need to ask
"How big a machine for 100 users?" you should NOT be building 100
user machines.  

My non-expert direct answer to your question:

Use multiple Asterisk servers not one big 4-CPU box.
This will scale well.  You might want to look into rack mount
boxes.  and move the non-PBX loads off the server.
With N boxes the G729 load will be spead over N cpus

If you think about it four single CPU boxes has 4X the
memory bandwidth and 4x the disk I/O bandwidth than a
4-way box and you will find you can buy four small rack mount
PCs cheaper then a big 4-CPU monster and, big AND here,
you have a failue plan, you can loos a box and not be
100% off the air, SOL. You should be looking for rack mount
PC boxes with dual power supplies and hot swap disks
People expect large PBXes to have uptime measured in years
and not have to go down for routine failures like smoking
power supplies or broken disk drives

> 
> Maybe you need to become more aquainted with asterisk. Pushing a
> system
> to near the limit is inviting disaster. You may need to reconsider
> the
> other tasks on this machine.
> 
> > I've seen Mark's post about being able to run 60 channels on a dual
> 1.8 
> > Xeon, but that unfortunately raises more questions than it answers.
> > 
> > You see, I may have to build many of these systems, and I need to
> find a 
> > good price/performance ratio, I can't simply go out and buy quad
> opteron 
> > systems for fun.  I was trying to find a processor for under $200
> to handle 
> > this.
> 
> $200 will get you a 2.6 P4 right now.  2 1.8s are just over your $200
> request. It will be as important to make sure you have a good
> motherboard and chipset.
> 
> > Given that, my question is: what constrains the G.729 codec? Is it
> mostly 
> > due to branches (implying a dual CPU or P4 HT architecture will be 
> > required) or is it mostly due to floating point (in which case a
> lower 
> > speed AMD might be able to accomplish the same task cheaper and
> better.)
> > 
> > Anyone have any ideas on this? Looking for feedback.
> 
> I think you will be running a lot of threads, so the extra cache and
> speed helps.
> 
> > BTW, can someone answer how the G.729 licensing works? If I change
> the CPU 
> > and motherboard (probably necessitating a kernel change), will my
> licenses 
> > still be valid? What exactly are they keyed to?
> 
> It is hardware based. If you change any of the major hardware, it
> will
> bark.
> 
> -- 
> Steven Critchfield  <critch at basesys.com>
> 
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=====
Chris Albertson
  Home:   310-376-1029  chrisalbertson90278 at yahoo.com
  Cell:   310-990-7550
  Office: 310-336-5189  Christopher.J.Albertson at aero.org
  KG6OMK

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