Optimizing WordPress on a VPS

Optimizing WordPress on a VPS – Pixzo technical guide

This article describes how to maximize WordPress performance on a Pixzo VPS, intended for administrators who configure the server themselves.

Requirements

- Server: Pixzo VPS with at least 2 GB RAM and 2 CPU cores - WP version: WordPress 6.5 or higher (check with `wp core version`) - PHP: 8.1 or 8.2 (check with `php -v`) - SSH access with root or sudo privileges - Web server: Nginx (recommended) or LiteSpeed - Optional: `wp-cli` (install with `curl -O https://raw.githubusercontent.com/wp-cli/builds/gh-pages/phar/wp-cli.phar`)

Steps

1. Optimize the web server and PHP stack

Use Nginx for better static file performance than Apache. Enable OPcache for PHP 8.2.

Open `/etc/php/8.2/fpm/php.ini` and modify these lines:

opcache.enable=1
opcache.memory_consumption=128
opcache.max_accelerated_files=10000

Restart PHP-FPM:

sudo systemctl restart php8.2-fpm

2. Configure PHP-FPM workers

Adjust the number of workers to your VPS resources. For 2 GB RAM and 2 cores: max 8 workers.

Edit `/etc/php/8.2/fpm/pool.d/www.conf`:

pm = dynamic
pm.max_children = 8
pm.start_servers = 4
pm.min_spare_servers = 2
pm.max_spare_servers = 4

Restart PHP-FPM:

sudo systemctl restart php8.2-fpm

3. Enable HTTP/2 in Nginx

Open `/etc/nginx/nginx.conf` and add to the `http` block:

server {
    listen 443 ssl http2;
    listen [::]:443 ssl http2;
}

Check configuration and restart:

sudo nginx -t && sudo systemctl restart nginx

4. Install page caching

For Nginx: use WP Rocket (plugin) and configure cache settings.

Install WP Rocket via WP-admin and set in Settings > WP Rocket > Cache: - Enable caching: on - Cache lifespan: 3600 seconds (1 hour)

Or use nginx-helper for a server-side cache:

sudo apt install nginx-common

Add to `/etc/nginx/sites-available/your-site`:

set $cache_uri $request_uri;
location ~* \.(jpg|jpeg|png|gif|ico|css|js)$ {
    expires 365d;
    add_header Cache-Control "public, immutable";
}

Test and restart:

sudo nginx -t && sudo systemctl reload nginx

5. Configure browser caching

Add the above cache headers to Nginx for static files.

In the same file, under `location ~* \.(jpg|jpeg|png|gif|ico|css|js)$`, also add:

add_header Cache-Control "public, immutable";

Reload Nginx.

6. Optimize images

Use `optipng` and `jpegoptim` for bulk reduction:

sudo apt install optipng jpegoptim
find /var/www/html/wp-content/uploads -name "*.jpg" -exec jpegoptim --strip-all --max=85 {} \;
find /var/www/html/wp-content/uploads -name "*.png" -exec optipng -o7 {} \;

Enable WebP support via WP Rocket (settings under Media).

7. Clean up the database

Use WP-Optimize:

wp plugin install wp-optimize --activate
wp db optimize

Delete expired transients and spammers:

wp transient delete --all
wp comment delete $(wp comment list --status=spam --format=ids) --force

8. Limit autoloaded options

Check autoload size:

wp option list --autoload=yes --format=total_size

If > 1 MB, find and delete unused options:

wp option list --autoload=yes --format=json | grep -E '"option_name":"(.*)"' | head -20
wp option delete unused_option_name

Verification

Check page speed with a tool:

curl -o /dev/null -s -w "Time total: %{time_total}\n" https://yoursite.nl

Normal load time < 500ms.

Check PHP-opcache status:

php -r "print_r(opcache_get_status());"

See `opcache_enabled` = true.

Frequently asked problems

Problem: Page cache does not work with Nginx and WP Rocket. Solution: Check whether the Nginx-helper plugin is activated and configure the cache location block correctly.

Problem: PHP-FPM crashes after worker config. Solution: Reduce `pm.max_children` to 4 and check RAM: `free -h`.

Problem: Images are not served in WebP. Solution: Install the Imagick PHP extension: `sudo apt install php8.2-imagick` and restart PHP-FPM.

With this configuration, WordPress runs on your Pixzo VPS without unnecessary database queries or unneeded PHP processes. What is your biggest performance bottleneck?