3000 Extensions with FreePBX


I have a project with 3000 users at first step and it will grow up to 4000 users. I want to know that is possible to implement it with FreePBX?
We uses Sangoma System 1000 and it’s ok. But for this scale I don’t have any experience with FreePBX/Asterisk.

Infrastructure is based on virtualization, so I want to use HA module too. with HA module, we can have more than 2 node? we can add more node for high availability?

Please let me use your experiences.


Good luck finding someone that’s battled this particular dragon and lived.

Big installations are relatively common, as are HA modules, but both together might be a challenge.

So is it possible?
FreePBX/Asterisk can handle this number of users?

What does it need for hardware process power? RAM, CPU?

Anybody has something like this system on the production?

You might be stretching FreePBX, reloading 3000 extensions will be burdensome, look to more granulation, a real SIP proxy at front ( I use kamailio) and several PBX’s to suit the clients. Virtualization makes that easy, The FreePBX HA solution is master/slave so that won’t work for more than two, b ut look to something like ProxMox and glusterfs/iscsi it is intrinisically master/master(master/master…) and you can have easy HA failover without needing multiple commercial licenses (only one instance will run at once)

Do you think that with more processing power, does it work?

Sangoma wants release a PBX with 5000 users based on FreePBX. So you think this can’t be pure FreePBX?

So you’re saying that I use Kamailio/OpenSIPS and just use FreePBX as media server?

That would be my choice Asterisk is a B2BUA it is very needy compared with a SIP proxy.

The 5000 extension system is pure Asterisk/Freepbx

And this is standard version ?

If the answer is yes, so do you test it in the field? as @dicko mentiond, reload can make issue, what do you think?

Ps: System 5000 is ready now?

I am not involved with this directly but yes it is the standard FreePBX. If you have followed along with 13 (and 14) development you will see there has been a lot of focus on performance. There also has been a focus on Asterisk performance. We (FreePBX and Sangoma) are developers and engineers. We are focused on pushing limits and breaking through barriers. We are not some guy with a bad haircut in his basement pushing bash scripts. We have teams doing NRE tasks and pushing both FreePBX and Asterisk to a level to rival and/or smash any proprietary solution. The team at Digium have the same goal. Offering solid solutions keep the lights on and the kids fed.


to address reload. a reload in 12 of 5000 extensions takes about 10 minutes. I believe in 13 we have that down under 2. In 14 This may get lower because of PHP 5.6+ opcache. We may be approaching disk i/o limits at some point

what’s about HA for it?
What’s Sangoma solution. You’re technical guys, so you’re finding the best :slight_smile:

HA will work the same as it does now.

With more than 2 nodes?

That’s not HA, that’s load balancing. Different thing.

We have an HA freePBX installation, installed from the distro ISOs with over 6000 extensions on it. It is running fine. Each node is an HP Gen 8 with 32 cores and 64 Gigs RAM. The biggest hit with this many extensions is it makes the GUI painfully slow when it has to load all the extensions just to modify 1 in the GUI, but it all works if you are patient.

In order to eliminate voice artifact over 200 concurrent calls, we had to tune the kernel parameters as described in this post: Tuning freePBX Kernel Virtual Memory Parameters

Note that this system is primarily used for voicemail and IVRs, so our concurrent call level never goes much above 300. However, it also never uses more than about 30% of system resources. Your mileage may vary. :slight_smile:

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