System Requirements/Sizing for FreePBX

Is there a sizing/system requirements doc for FreePBX? I built my system just by getting something new and decent but have no documentation on what is really needed and how to size it.

I have 2 SIP trunks, 2 phones and I am running a dual core intel 2.53ghz and 2GB ram and a 250GB hard drive and g729 codec. I have no problems at all but just curious if I were to install a large setup how would I calculate what I need hardware wise.


That’s not an easy question to answer, you will see similar questions asked generically about Asterisk in general and a whole range of answers.

It depends on everything from how much trans-coding, if any, you are doing, frequency of calls, duration of calls, features being used, external effects such as XML application usage by phones if any, usage of FOP or other desktop tools, etc, etc…

So … given the number of factors, it’s not really possible to give a generic answer.

On the positive side, hardware is cheap, so it never hurts to overkill a system by a little bit. You would spend more time (time == money) trying to figure out an answer then just purchasing a reasonably performing system…

I agree with p_lindheimer in that it’s easy to just purchase a hardware rig that will more than support the requirements of even a heavy-use PBX (eg, for a call-center) however it would be useful if some ubernerd were to devise a matrix listing resource requirements for various call/channel/feature volumes, for the purpose of cloud-based PBX systems.

ie, it may be more suitable to have a PBX hosted on a RackspaceCloud or AmazonAWS server, rather than investing in actual hardware. In the case of a RackspaceCloud server, will their basic $11/mo server cut the mustard?

256 MB RAM & 10 GB HDD seems like it might be a bit slim, but for a mom’n’pop shop who just wants to have an automated voice menu and aren’t expecting to have the phone ringing off the hook all day long, maybe 256 MB RAM would be enough to operate such a PBX.

Anyone have any comments they’d like to throw in the ring?

making a decision between cloud and premise is not really related to sizing, there are many other considerations.

Furthermore, there are also more important things to look at when considering dedicated hardware vs. virtual environments since you are dealing with a realtime system.

There are some companies who have figured out ‘how to do it properly’ on virtual environments and others who have not (but still sell slices of systems as PBX’s)

These tend to be the first order of consideration when making such an evaluation, before even thinking about performance needs.

I can see how somebody may be swayed by wanting a virtual PBX from a company who sells it for only $12/month but I personally would like the hardware in my possession and total control over it. The initial cost of the hardware may be a little high but just think of it this way: you can upgrade it whenever you want for a one time price. Want more RAM in your machine? Buy more and install it. I know regular hosting providers charge extra per month for something like this (not sure about pbx services).

I don’t know enough about the codec you’re using but I have heard it requires more processing power than something like the g711 codec but it would pay off with the bandwidth usage.

If I was building an aserisk box, I would bump up the specs a little from what you have. The hdd should be plenty but slightly more RAM and slightly faster processor would be what I change.