Monitorix will allow you to monitor many parameters of your server in the form of graphs and charts: https://www.monitorix.org/screenshots.html

-- Monitorix installation --

On Linux Debian/Ubuntu, this should work:

Code:
sudo apt install monitorix && systemctl status monitorix
Edit configuration file shown in above output:

Code:
sudo nano /etc/monitorix/monitorix.conf
Inside make sure is:
Code:
<httpd_builtin> 
        enabled = y
        log_successful_requests = n

        <auth> 
                enabled = y
Install apache2-utils to generate htpasswd file for password protection of the web interface (<auth> was enabled above):
Code:
sudo apt install apache2-utils && htpasswd -d -c /var/lib/monitorix/htpasswd admin
Apply changes:
Code:
systemctl restart monitorix
Open web interface/panel: http://your-server-ip:8080/monitorix

Just one of many monitored aspects of your server: