High Availability and other commercial modules

When using High Availability for two servers and wanting to purchase other commercial modules, do I have to buy two licenses for each additional commercial module?

Does anyone know that?

Yes, you will need a license for each server. You also have to purchase 2 licenses for the HA module, one for each server.

Does HA require a whole new install of freepbx distro or can it just be added to an existing system?

There is a wiki that explains much of this.

http://wiki.freepbx.org/display/FCM/FreePBX+High+Availability

However, to answer your question. You have to select an HA options on install so it can’t just be added to an existing system.

Thank you.
I wasn’t sure because on my FreePBX GUI without having HA selected on install, I can still click on the High Availability link where I am given an option to purchase. This makes me think that I can add it to an existing system.
As this is somewhat confusing, you could mention in below menu that when adding HA, a new install is required.

Also when selecting HA upon install, do I need a license key for HA right away for freePBX to be installed and to work at all?