Hardware requirements

Here’s a question that has been asked many times, but I haven’t really found a good answer (could be bad searching skills…).

How “fast” a system do you need for a small PBX?

I have an AsteriskNow install running on an ancient industrial PC. It includes a 500MHz Celeron CPU, 128MB RAM and an 8GB flash disk. Right now 3 phones and a SIP trunk are connected, and everything seems to work fine. But when the system is fully installed about 10 phones, the SIP trunk and perhaps an analogue line will be in use. Is that likely to work? And if not, what would be the bottleneck?

The system uses G711a, no transcoding, and maximum 3-4 concurrent calls.

Yes, I could buy a dual Xeon server with 8GBs of RAM, but I like small, quiet (no moving parts) and low power consumption.

And a related question. How much FPU power is needed? Another nice, quiet, option would be a Via Mini-ITX board. They have reasonably fast CPUs, but the FPU is not that great. Is that a problem, again assuming transcoding is not needed?

Best regards,

Mikkel C. Simonsen

Of course it’s complex - that’s why I asked for some pointers.

So the CPU requirements are not that high, if you don’t need to do a lot of transcoding. VIA CPUs are out.

I know 128MB is low. That particular board would not recognize “modern” memory modules, so 128MB was all I could find. I have replaced that board with a more recent GeodeNX board now…

But when is disk performance critical? When you do a lot of recording? On the systems I have worked on so far (with moderate or no VM usage, and no recording), low speed flash drives have worked fine. The only difference I can detect, is the boot speed and the speed of the web interface. I have detected no differences in actual use.

Best regards,

Mikkel C. Simonsen

The subject is simply far more complex than you are stating. Many factors contribute to the server specifications, CPU bandwidth is just one of many considerations.

For quite a long time we used 700Mhz Pentium III’s with 512M of RAM. 128M of RAM is really light.

You are correct in stating the g.729 adds transcoding overhead.

Disk performance is also critical. One of our new install with 176 extensions, 3 call Queues, iSymphony and Queuemetrics is being installed on a dual quad core Xeon with 8M RAM. More importantly than raw power it also has two SSD’s RAID 1 for the OS and Asterisk and two 500M SATA’s for call recording storage.

At the other end of the spectrum we have great luck with the Intel Atom processors and SSD’s for a no moving parts system.

The VIA processors don’t work real well with CentOS and Asterisk I would stay clear.

Not an interesting topic it seems. Everybody else must be using dual Xeon systems :wink:

Here are a couple of more working set-ups for “inspiration”:

AthlonXP 2000+, 1GB RAM, 40GB oldish IDE drive, 10 SIP phones, some voicemail usage.

Celeron (P4) 1.8GHz, 512MB RAM, 4GB IDE DOM, 20 SIP phones, no voicemail

Both systems use SIP trunks only.

Best regards,

Mikkel C. Simonsen


I’m running a fairly modest system (8 extensions, though most with H.264 video capability) using a Foxconn Nettop NT-3500 unit. I had a 4GB SoDIMM and a spare SSD lying around, so have dropped those in.

For something so cheap, the specs are not too shabby and you get a 1.6 GHz dual-core AMD CPU included. Performance to date has been absolutely fine. My system fully boots from cold, with Asterisk and FPBX running in around 50 seconds.

My ‘hardware redundancy’ solution is another NT-3500 sitting on the shelf!

when you visit your site there is no “minimum hardware requirements” section and it is ridiculous that you need to search the forums for such information.