Reducing Server Load: Measure Before Tuning PHP-FPM

High CPU load on a web server can come from slow application queries, runaway workers, scheduled jobs, traffic spikes, or external scans. Increasing worker limits without identifying the cause may make resource contention worse.

Start by measuring CPU, memory, I/O wait, load average, and the processes consuming resources. Correlate the time window with web access logs, PHP-FPM status, database activity, and scheduled tasks. If one account is responsible, inspect its workload before changing server-wide limits.

For PHP-FPM, tune process counts based on available memory and observed request duration. More workers can increase concurrency but also consume more RAM and create more simultaneous database work. Use slow logs and application profiling to identify expensive requests, and check whether cache misses or repeated background actions are driving load.

After a change, compare the same metrics and representative requests. Record the original values and keep a rollback path. Sustainable performance improvements usually come from removing unnecessary work, optimizing queries, and controlling background jobs rather than merely raising limits.