PHP & lsphp Tuning

OpenLiteSpeed uses lsphp — a PHP build that communicates via LSAPI, which is faster than FastCGI. This page covers every tuning point you will encounter.

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How lsphp Works

Browser Request
  └── OLS Listener
       └── Virtual Host
            └── scripthandler: lsapi:lsphp84
                 └── lsphp process (pool via LSAPI socket)
                      └── executes .php, returns response

LSAPI is a persistent connection protocol. Workers are kept alive between requests (unlike traditional CGI), which avoids fork overhead.

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File Paths — PHP Quick Reference

# PHP binaries by version
/usr/local/lsws/lsphp84/bin/lsphp    # PHP 8.4
/usr/local/lsws/lsphp83/bin/lsphp    # PHP 8.3
/usr/local/lsws/lsphp82/bin/lsphp    # PHP 8.2
/usr/local/lsws/lsphp81/bin/lsphp    # PHP 8.1

# php.ini location (for each version)
/usr/local/lsws/lsphp84/etc/php/8.4/litespeed/php.ini

# Additional ini files (conf.d)
/usr/local/lsws/lsphp84/etc/php/8.4/litespeed/conf.d/

# OPcache ini (usually auto-loaded)
/usr/local/lsws/lsphp84/etc/php/8.4/litespeed/conf.d/10-opcache.ini

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External App Settings (httpd_config.conf)

The extprocessor block controls how OLS manages the lsphp pool.

Tuned extprocessor block

extprocessor lsphp84 {
  type                    lsapi
  address                 uds://tmp/lshttpd/lsphp84.sock

  # Path to PHP binary
  path                    /usr/local/lsws/lsphp84/bin/lsphp

  # Max simultaneous connections from OLS to this PHP pool
  maxConns                35

  # PHP children per instance
  env                     PHP_LSAPI_CHILDREN=35

  # Fork avoidance: don't fork new processes for responses < this size
  env                     LSAPI_AVOID_FORK=200M

  # Keep connection alive after request (persistent)
  persistConn             1

  # Seconds to wait for first response
  initTimeout             60

  # Worker instances (1 is fine for most single-server setups)
  instances               1

  # Memory limits per worker process
  memSoftLimit            2047M
  memHardLimit            2047M

  # Max PHP child processes (hard cap)
  procSoftLimit           400
  procHardLimit           500

  # Queue backlog
  backlog                 100

  # Auto-start workers at server start
  autoStart               2

  # Priority (nice value, 0 = default)
  priority                0
}

Key Tuning Parameters

Parameter	Conservative	Moderate	Aggressive
maxConns	10	35	100+
PHP_LSAPI_CHILDREN	10	35	100+
procSoftLimit	100	400	1000
memSoftLimit	512M	2047M	2047M

For a 2 GB RAM VPS running a WordPress site: maxConns 10, PHP_LSAPI_CHILDREN 10.

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php.ini — Critical Settings

/usr/local/lsws/lsphp84/etc/php/8.4/litespeed/php.ini

; ============================================================
; MEMORY
; ============================================================
memory_limit = 256M          ; 128M for light sites, 512M for WooCommerce

; ============================================================
; EXECUTION
; ============================================================
max_execution_time = 60       ; seconds — increase for imports/exports
max_input_time = 60
max_input_vars = 5000         ; WordPress may need 5000+

; ============================================================
; UPLOADS
; ============================================================
upload_max_filesize = 64M
post_max_size = 64M

; ============================================================
; OUTPUT
; ============================================================
output_buffering = 4096

; ============================================================
; ERROR HANDLING (production: off; dev: on)
; ============================================================
display_errors = Off
log_errors = On
error_log = /usr/local/lsws/logs/php-error.log
error_reporting = E_ALL & ~E_NOTICE & ~E_DEPRECATED

; ============================================================
; SESSION
; ============================================================
session.gc_maxlifetime = 1440
session.cookie_secure = 1
session.cookie_httponly = 1
session.cookie_samesite = Strict

; ============================================================
; DATE
; ============================================================
date.timezone = UTC

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OPcache — Must-Enable

OPcache is the biggest single PHP performance improvement. It caches compiled PHP bytecode in memory.

opcache settings in php.ini or conf.d/opcache.ini

; Enable OPcache
opcache.enable = 1
opcache.enable_cli = 0

; Memory for compiled scripts (MB)
opcache.memory_consumption = 128

; String interning memory
opcache.interned_strings_buffer = 16

; Max cached files
opcache.max_accelerated_files = 10000

; Revalidation interval (0 = never check filesystem, fastest)
; Set 0 in production, 2 in development
opcache.revalidate_freq = 0

; Pre-load scripts at startup (PHP 7.4+)
; opcache.preload = /var/www/site/preload.php
; opcache.preload_user = nobody

; JIT (PHP 8.x)
opcache.jit_buffer_size = 64M
opcache.jit = tracing

OPcache Quick Check

# Is OPcache enabled?
/usr/local/lsws/lsphp84/bin/lsphp -r "echo opcache_get_status() ? 'OPcache ON' : 'OPcache OFF';"

# Check from a PHP info page
/usr/local/lsws/lsphp84/bin/lsphp -r "phpinfo();" | grep -i opcache

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Per-Vhost php.ini Overrides

You can override php.ini values per virtual host without touching the global ini.

vhconf.conf — phpIniOverride

phpIniOverride  {
  php_value memory_limit 512M
  php_value upload_max_filesize 128M
  php_value post_max_size 128M
  php_value max_execution_time 120
  php_admin_value open_basedir /var/www/example.com/:/tmp/
}

php_admin_value

php_admin_value sets values that cannot be overridden by scripts or .user.ini. Use for security-sensitive settings like open_basedir.

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PHP Extension Management

# Install common extensions (Debian/Ubuntu)
sudo apt install lsphp84-redis         # Redis session/cache
sudo apt install lsphp84-imagick       # Image processing
sudo apt install lsphp84-mbstring      # Multi-byte strings
sudo apt install lsphp84-xml           # XML support
sudo apt install lsphp84-curl          # cURL
sudo apt install lsphp84-zip           # ZIP
sudo apt install lsphp84-intl          # Internationalization
sudo apt install lsphp84-gd            # GD image library

# Verify extension loaded
/usr/local/lsws/lsphp84/bin/lsphp -m | grep -i redis
/usr/local/lsws/lsphp84/bin/lsphp -m | grep -i opcache

# List all loaded extensions
/usr/local/lsws/lsphp84/bin/lsphp -m

# Check extension path
/usr/local/lsws/lsphp84/bin/lsphp -r "echo ini_get('extension_dir');"

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Switching PHP Version for a Vhost

# 1. Install the desired version
sudo apt install lsphp83 lsphp83-common lsphp83-mysql

# 2. Add extprocessor block in httpd_config.conf
sudo vim /usr/local/lsws/conf/httpd_config.conf
# Add lsphp83 block (copy lsphp84 block, change paths)

# 3. Update vhconf.conf scripthandler
sudo vim /usr/local/lsws/conf/vhosts/example/vhconf.conf
# Change: lsapi:lsphp84 → lsapi:lsphp83

# 4. Reload
sudo /usr/local/lsws/bin/lswsctrl restart

# 5. Verify PHP version served (create info.php in web root)
echo "<?php phpinfo();" | sudo tee /var/www/example.com/public/info.php
curl -s http://example.com/info.php | grep "PHP Version"
# Delete after checking!
sudo rm /var/www/example.com/public/info.php

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PHP Diagnostics

# Check PHP version
/usr/local/lsws/lsphp84/bin/lsphp -v

# Check all php.ini values
/usr/local/lsws/lsphp84/bin/lsphp -r "phpinfo();" 2>/dev/null | grep -E "memory_limit|upload_max|max_execution"

# Check OPcache status
/usr/local/lsws/lsphp84/bin/lsphp -r "var_dump(opcache_get_status(false));"

# How many lsphp processes right now?
ps aux | grep lsphp | grep -v grep | wc -l

# PHP error log location
/usr/local/lsws/lsphp84/bin/lsphp -r "echo ini_get('error_log');"
sudo tail -20 /usr/local/lsws/logs/php-error.log

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Common PHP Problems

Problem	Cause	Fix
PHP files download instead of execute	No scripthandler for .php	Add scripthandler { add lsapi:lsphp84 php }
500 error on PHP pages	php.ini error or missing extension	Check /usr/local/lsws/logs/error.log
Memory exhausted	memory_limit too low	Increase in php.ini or phpIniOverride
Upload fails	upload_max_filesize or post_max_size too small	Increase both in php.ini
Session not persisting	Wrong session path/perms	Check session.save_path writable by nobody
OPcache not refreshing	revalidate_freq=0 in prod	For dev: set opcache.revalidate_freq=2
Wrong PHP version served	Old extprocessor/scripthandler	Verify vhconf.conf scripthandler and reload