The Complete WordPress Performance Checklist

Series: WordPress Performance on DirectAdmin (Rocky Linux 9)

Phase 8: Authority & Wrap-Up — Part 29 of 30

The Complete WordPress Performance Checklist for DirectAdmin on Rocky Linux 9

Introduction

This checklist distills actionable steps for sysadmins seeking optimal WordPress performance on DirectAdmin-managed Rocky Linux 9 servers. It covers server, PHP-FPM, webserver, and WordPress-level improvements. Each step highlights DirectAdmin specifics, safe-by-default commands, and practical testing methods. Validate all changes in staging before production deployment.

1. System and OS-Level Tuning

Keep Rocky Linux 9 Updated:
```
sudo dnf update -y
```
Schedule regular OS updates and reboot for kernel/security patches. Test updates in a non-production environment first.

Optimize Swappiness:

sudo sysctl vm.swappiness=10
echo 'vm.swappiness = 10' | sudo tee /etc/sysctl.d/99-swappiness.conf
sudo sysctl --system

Reduces swap usage for better performance on memory-constrained servers.

Review Resource Limits:
```
ulimit -n
```
For high-traffic sites, increase open file limits in /etc/security/limits.conf if needed.

Disable Unnecessary Services:

sudo systemctl list-unit-files --state=enabled
sudo systemctl disable --now bluetooth cups

Keep only essential services enabled.

2. DirectAdmin Webserver and PHP-FPM Configuration

Webserver (NGINX or Apache)

Check Which Stack is Active:

sudo /usr/local/directadmin/custombuild/build used_configs

NGINX: Tune worker settings in /etc/nginx/nginx.conf:
```
worker_processes auto;
worker_connections 4096;
```
Reload NGINX after changes:
```
sudo systemctl reload nginx
```

Apache: Adjust /etc/httpd/conf/extra/httpd-mpm.conf for event MPM:

StartServers 2
MinSpareThreads 25
MaxSpareThreads 75
ThreadsPerChild 25
MaxRequestWorkers 150
MaxConnectionsPerChild 1000

Reload Apache:

sudo systemctl reload httpd

DirectAdmin Webserver Templates:
For persistent tuning, update custom templates in /usr/local/directadmin/data/templates/ and rebuild configs:
```
cd /usr/local/directadmin/custombuild
sudo ./build rewrite_confs
```

PHP-FPM Pool Tuning

Locate Pool Configs: /usr/local/phpXX/etc/php-fpm.d/USERNAME.conf (where XX is PHP version)

Recommended Starting Values for Moderate Traffic:

pm = dynamic
pm.max_children = 20
pm.start_servers = 4
pm.min_spare_servers = 2
pm.max_spare_servers = 6
pm.max_requests = 500

Edit with sudo vi and reload PHP-FPM:

sudo systemctl reload php-fpmXX

Adjust for each domain as needed.

Increase memory_limit for large sites:
```
php_admin_value[memory_limit] = 256M
```

OPcache

Check if enabled:
```
php -i | grep opcache
```

Default OPcache values in /usr/local/phpXX/lib/php.ini:

opcache.enable=1
opcache.memory_consumption=128
opcache.interned_strings_buffer=16
opcache.max_accelerated_files=8000
opcache.revalidate_freq=60

Reload PHP-FPM after changes.

3. Database Optimization (MariaDB/MySQL)

Set Sensible Defaults in /etc/my.cnf.d/server.cnf:
```
[mysqld]
innodb_buffer_pool_size=512M
innodb_log_file_size=128M
max_connections=100
query_cache_type=0
query_cache_size=0
```
Adjust innodb_buffer_pool_size to 60–70% of available memory on DB-only servers.

Warning: Changing innodb_log_file_size requires DB service restart and can cause downtime. Plan accordingly.
Restart MariaDB safely:
```
sudo systemctl restart mariadb
```
Test DB status:
```
mysqladmin -u root -p status
```

4. WordPress Core, Plugins, and Theme Best Practices

Keep Core, Plugins, and Themes Updated:

wp core update
wp plugin update --all
wp theme update --all

Audit Plugin/Theme Load:
```
wp plugin list
wp theme list
```
Deactivate and remove unused or heavy plugins/themes.
Minimize Autoloaded Options:
```
wp option list --autoload=on --fields=option_name,size --order=desc --field=option_name
```
Large autoloaded options slow every page load. Optimize as needed.

5. Caching and Content Delivery

Enable Full Page Caching:
- Recommended: Use a plugin like WP Super Cache or W3 Total Cache.
- Test cache status:
- ```
curl -I -H 'Cache-Control: no-cache' https://example.com/
```

Static Asset Caching (NGINX/Apache):

NGINX: Add to location ~* \.(js|css|png|jpg|jpeg|gif|ico)$ block:

expires 30d;
add_header Cache-Control "public, immutable";

Apache: In .htaccess or site config:

<IfModule mod_expires.c>
  ExpiresActive On
  ExpiresByType image/png "access plus 30 days"
  ExpiresByType text/css "access plus 7 days"
</IfModule>

Leverage a CDN for Global Assets:
Update DNS or use a plugin to offload media. Verify CDN response with:
```
curl -I https://cdn.example.com/path/to/image.jpg
```

6. Security and HTTP/2

Enable HTTPS Everywhere:

sudo dnf install certbot
sudo certbot --nginx -d example.com -d www.example.com

Or use DirectAdmin’s SSL interface. Test with:

curl -I https://example.com/

Force HTTP/2:
- NGINX: Ensure listen 443 ssl http2; in server block.
- Apache: Enable mod_http2 and add Protocols h2 http/1.1 to vhost.
- Test with:
- ```
curl -I --http2 https://example.com/
```

Harden PHP:

disable_functions = exec,passthru,shell_exec,system
expose_php = Off

Set in php.ini or pool config.

Check Server Firewall:

sudo firewall-cmd --list-all
sudo firewall-cmd --permanent --add-service=https
sudo firewall-cmd --reload

7. Monitoring, Logging, and Testing

Monitor Server and Application Logs:

sudo tail -f /var/log/nginx/access.log /var/log/nginx/error.log
sudo tail -f /var/log/httpd/access_log /var/log/httpd/error_log
sudo tail -f /var/lib/mysql/mariadb.log
sudo tail -f /var/log/php-fpm/www-error.log

Profile Performance:

WP-CLI:
```
wp profile stage --all
```
Load Testing:

wrk -t4 -c40 -d30s https://example.com/
k6 run script.js

Set Up Uptime and Resource Monitoring:
Use systemctl status, top, htop, and third-party monitoring as needed.

8. Routine Maintenance and Review

Document all configuration changes and keep versioned backups.
Schedule regular reviews for plugin/theme bloat, database size, and log anomalies.
Test failover and backup restores quarterly.

Quick Reference Checklist

OS and DirectAdmin fully updated
Webserver and PHP-FPM pools tuned per domain
OPcache and database configured for available resources
WordPress core/plugins/themes minimal and current
Caching and CDN implemented
HTTPS and HTTP/2 enforced
Firewall, logs, and monitoring in place
All changes tested before production deployment

Testing Changes and Rollback

Test in staging first.
After any config change, reload/restart only the affected service; use systemctl and monitor logs.
Use wp-cli and curl to verify WordPress is healthy post-change.
Keep recent config and DB backups for fast rollback.

Note: This article offers general technical guidance. Validate all configurations in a safe environment before applying them to production.

Previous: How to Measure Real WordPress Performance (Not PageSpeed Scores)

Next: The Ideal WordPress Performance Stack for a DirectAdmin VPS