PHP-FPM pool reached pm.max_children: fix guide
TL;DR
All PHP-FPM workers are busy — requests queue, latency spikes, and nginx may return 502/504.
Key facts
- Topic
- Production error triage
- Stack
- PHP
Quick sizing
Use the PHP-FPM calculator to estimate pm.max_children from RAM and expected per-request memory.
Reflex playbooks detect pool saturation early and can recycle workers when policy allows.