Process Limits

Learning Focus

By the end of this lesson you will know how to set PHP process limits to balance concurrency against available resources.

What Process Limits Control

Process limits determine how many PHP workers run simultaneously to handle requests. This is set in the external application configuration via Max Connections.

Impact of Wrong Sizing

Setting	Too Low	Too High
Max Connections	Requests queue, slow responses	Memory exhaustion, swapping, crashes

Sizing Approach

1. Calculate available RAM after OS, OpenLiteSpeed, and database
2. Divide by per-worker memory usage (from ps monitoring)
3. Set Max Connections to that number minus a safety margin

# Check per-worker memory usage
ps aux | grep lsphp | awk '{print $6/1024 " MB"}'

# Count current workers
ps aux | grep lsphp | grep -v grep | wc -l

Server RAM	Available for PHP	Worker memory	Max Workers
1 GB	~600 MB	80 MB	7
2 GB	~1.2 GB	80 MB	15
4 GB	~2.5 GB	100 MB	25
8 GB	~5 GB	100 MB	50

Configuring in WebAdmin

1. Server Configuration → External App → select your lsphp app
2. Set Max Connections to your calculated value
3. Save and Graceful Restart

info

Monitor PHP worker usage under real traffic patterns. Adjust based on actual measurements rather than theoretical calculations.

Key Takeaways

• Right-size PHP workers from available RAM and measured per-worker memory, not guesswork.
• Too few workers increase queueing; too many workers cause swap pressure.
• Monitor and adjust under real traffic patterns.

What's Next

• Return to the PHP Integration module for the complete overview.