FreePBX requirements: capacity and deployment checklist

A minimum is not a capacity rating

The official FreePBX installation path describes requirements to install the platform. Production capacity depends on simultaneous calls and the work done on those calls. Recording, transcoding and conferencing can change resource use substantially without changing extension count.

Write down expected busy-hour activity before choosing a VM or appliance. Include queues, external forwarding and integration processes. Identify whether other applications share the host and whether the environment offers predictable CPU and storage performance.

Plan the storage lifecycle

Separate configuration, voicemail, recordings, logs and backups. Recording retention can dominate storage; a backup kept only on the same disk does not protect against loss of that disk. Decide who may retrieve recordings and how retention is enforced.

Measure growth after a pilot period. Include room for updates and maintenance operations, and alert before disks fill. Avoid treating a large disk as a replacement for a retention policy.

Plan the non-CPU dependencies

Confirm stable addressing or name resolution, time synchronization, power protection and a supported network path for phones and trunks. Establish how administrative access works when an ordinary workstation or office link is unavailable.

The FreePBX 17 baseline here is Debian 12. Verify hardware drivers, virtualization support and the official install path before choosing an image merely because it is the newest Debian release.

Validate a realistic load

Create a representative test including the features you will actually use. Observe CPU, memory, storage latency and call behavior under expected peak conditions. Document what was tested and retain margin for growth. No generic extension-to-vCPU multiplier can replace that workload validation.