This is more of a request for general advice than to solve a specific problem. I am new to FreePBX/Asterisk and slowly (but surely) learning how to configure it, with articles on this forum being a great help so far. I am currently trying to implement a small deployment at home (with an external link to my Voip service and no more than 3 extensions). I may be doing a slightly larger (but still small) deployment somewhere else after this.
For ease and quickness, I initially set up the system on a Raspberry Pi using the pre-built RasPBX system. The only problem with this is that it is currently at version 15 of FreePBX and as far as I can tell, it is possibly not straightforward to upgrade. I have also installed the latest FreePBX download on a virtual machine just to see how it compares, and can see straight away that it would be advantageous to go with version 16 if at all possible.
The hardware platform that I eventually go with depends on a number of factors, but there are two questions in my mind for which opinions would be greatly valued.
Which of a Raspberry Pi (3B/4) or a virtual machine (which would be running under VirtualBox on a Linux host) is likely to give better performance, or is there not much to choose between them?
I have found a number of articles online about installing FreePBX on a Raspberry Pi and they seem quite involved. If this is the way to go, can anyone recommend a good and reliable article on the subject?
Raspberry Pi sounds perfect for your use case. Unless you need some specific functionality of 16 (I cannot think of a big one off the top of my head), I would wait. While 17 is in beta, it will likely be out sooner rather than later.
The only other thing I would add to this is that sometimes SD cards can be finicky, and corruption can happen. A regular SD backup or more ideally moving to booting off an SSD.
The resources required to handle calls is greatly dependent on how the RTP packets are being processed. If Asterisk is set up to transcode Opus, encrypt/decrypt and record the call, it takes more than ten times the resources, compared to just passing packets between extension and trunk.
An RPi 3B can easily handle 10 concurrent calls, if not transcoding or recording. With transcoding and recording, the limit is probably about 3. Idle extensions and trunks are a negligible load; with 20 extensions, concurrent call limitations would be about the same. On a “lab” system, you might be spending a lot of time in the GUI and it could get annoying if it’s too sluggish. You already have that experience and can decide whether it matters.
If you want to run FreePBX 16 (or even 17) on a Pi, see
Although a Pi is pretty cheap, by the time you add a high-endurance SD card, case and reliable power supply, you’re in the $100 range. For not much more, you can get an Intel/AMD architecture machine that can run the FreePBX Distro, and be up and running in a few minutes. You’ll also have commercial modules available, and support from a much larger community. For example, see Amazon.com @ $139, though you can likely find something similar for less.
Yet another option is running in the cloud. If your power or internet goes down, the system continues to function, sending calls to mobile phones or voicemail. If the software fails, it’s trivial to restore from a snapshot or backup. If the hardware fails, the cloud service provides a replacement. Most cloud services offer a free trial, so you can experiment at no cost.
For a home system like yours there are some other good options for implementing Asterisk and FreePBX. You might take a look at this link for some ideas.
Many thanks to everyone for all the answers and it was useful receiving a wide range of views - plenty to think about.
My home installation is now up and running with FreePBX 15 on the Raspberry Pi, and so as it is working, I think I will stick with it at least for the time being. As for the other deployment, I have yet to decide what to do. The cheap cloud option (which I had not realised existed) may be worth serious consideration.