[asterisk-users] Scaling

Gordon Henderson
Wed, 17 Jun 2009 12:51:57 -0000

On Wed, 17 Jun 2009, Steve Totaro wrote:

> Hi,
>
> Quick question to the real world.
>
> Approx what specs would I need on server to handle 95 ZAP or Dahdi ->
SIP
> gateway using G729 on the SIP to carrier side (nothing else, just media
> conversion)?
>
> Does the latest Asterisk/DAHDI significantly improve these numbers over
say,
> Asterisk 1.2.X?
>
> Sure, there is plenty to read but nothing I could find quickly on my exact
> needs that was clear and I want to be fairly sure before ordering a server.
>
> Obviously load avg has something to do with it but CPU and mem seems to be
> the biggest factors.

Transcoding - It's CPU grunt and multi processors what you need (more so
than memory) - handling that many calls ought to be a breeze on any modern
hardware without the transcoding. Personally, I think I'd be looking at a
TC400B card which can handle 96 concurrent g729 transcodes...

But as a rough benchmark, I can do 12 concurrent g729 transcodes on a 1GHz
VIA processor before it's totally maxed out, (stupid) extrapolation to 96
would suggest 8 x 1GHz processors, 4 x 2GHz, or 3 x 3GHz processors...
However you gain more with the faster processors in terms of bigger cache
(but that can also be a loss too) I'd start with a quad core system and
see how it goes under benchmark...

Gordon