So please excuse my loose use of the PBX / VoIP terminology as I have just recently been introduced to these services.
Essentially I was tasked with building a solution with FreePBX (without GUI and Asterisk only is okay too) and make it scalable. How our system works is we have internal calling between our team members but we do PSTN calls as well. The outbound PSTN calls will be placed with Twilio (this allows us to support E911 emergency calling) and it just simplifies everything.
The issue I ran into is scaling our server side of things. I did some light reading on High Availability and Load balancing here: High availability Asterisk options?. What I intend to do is deploy a couple droplets on DigitalOcean (DO) $15+ droplets and load balance them to one url endpoint from Twilio using round-robin load balancing from DO. The database on the other hand would also be using DO but their managed DBs, so that the databases can automatically scale. This way, the data is always synced to each instance of FreePBX (I think?) and we don't have any issues with server load.
Does this seem like a viable solution or would there be issues involved with this? We absolutely need Twilio as our backend for PSTN's and we need this to be scalable for thousands of users and concurrent calls.
Note: Twilio's internal SIP Trunking is not good enough for us because it does not offer Emergency 911 calls, only their Elastic SIP Trunking allows this :)
Thank you!
