running a php task every 24 hours

This is exactly what Cron (linux) or Scheduled Tasks (windows) are for.

You can run them on your application server to keep everything in one place.

For example, I have a cron running on my home server to backup its MySQL databases every day. Only one system is involved in this process.

Adding 0 0 * * * php /path/to/your/cronjob.php to your crontab should accomplish this.