PHP LSAPI Configuration

LiteSpeed API (LSAPI) is the PHP execution mode used by LiteSpeed Web Server. It is significantly faster than PHP-FPM because it shares memory between the web server and PHP processes, eliminating the inter-process communication overhead of FPM sockets.

Why LSAPI is faster than PHP-FPM

Mode	PHP process lifecycle	IPC overhead
mod_php	New process per Apache worker	None (in-process)
PHP-FPM	Persistent pool, Unix socket	Socket per request
LSAPI	Persistent pool, shared memory	Near-zero

LSAPI workers stay running between requests (like FPM) but communicate through LiteSpeed's internal memory bus rather than a socket. For CPU-bound PHP applications, this is typically 40–50% faster than FPM.

Checking LSAPI is active

# Verify LiteSpeed is using LSAPI
/usr/local/lsws/bin/lswsctrl status

# Check PHP handler in LiteSpeed config
grep -r "lsphp\|lsapi" /usr/local/lsws/conf/httpd_config.conf

In WHM, verify under Software → MultiPHP Manager — PHP versions should show as ea-php82 (EasyApache) running through LSAPI.

Configuring LSAPI worker processes

Edit the LSAPI configuration in the LiteSpeed WebAdmin console (https://YOUR_IP:7080):

Server → External App → lsphp (or the specific PHP version):

Setting	Default	Recommended for high traffic
Max Connections	35	100–200
Initial Request Timeout	60s	60s
Retry Timeout	0	0
Persistent Connection	Yes	Yes
Auto Start	Yes	Yes

Per-account PHP settings

For cPanel servers, LSAPI respects php.ini values set through:

1. cPanel → Software → MultiPHP INI Editor — GUI for common settings
2. .htaccess directives — php_value, php_flag
3. Custom php.ini in the document root

# Create a custom php.ini for a specific account
cat > /home/username/public_html/php.ini << EOF
memory_limit = 512M
upload_max_filesize = 64M
post_max_size = 64M
max_execution_time = 300
opcache.enable = 1
opcache.memory_consumption = 128
opcache.max_accelerated_files = 10000
EOF

OPcache tuning

OPcache is critical for PHP performance — it caches compiled bytecode so PHP files don't need to be parsed on every request.

; Recommended OPcache settings for WordPress/WooCommerce
opcache.enable = 1
opcache.memory_consumption = 256
opcache.interned_strings_buffer = 16
opcache.max_accelerated_files = 20000
opcache.revalidate_freq = 60
opcache.fast_shutdown = 1
opcache.enable_cli = 0

Add these to the account's php.ini or via the cPanel MultiPHP INI Editor.

Monitoring PHP performance

# Check LSAPI worker status
/usr/local/lsws/bin/lswsctrl status

# Watch real-time PHP process usage
watch -n1 "ps aux | grep lsphp | grep -v grep | wc -l"

# Check OPcache statistics (create temporarily)
echo "<?php opcache_get_status(true) | json_encode | print;" > /tmp/opcache_check.php
php /tmp/opcache_check.php | python3 -m json.tool | grep -E "hit_rate|memory_usage"
rm /tmp/opcache_check.php

A healthy OPcache hit rate is above 95%. Below that, either max_accelerated_files is too low or memory_consumption needs to be increased.