A few notes on my Observium setup on a Debian 8 Jessie system. All configuration options and details can be found at the Observium documentation page.

Bad Interfaces

These entries are in /opt/observium/config.php

$config['bad_if'][] = voip-null;
$config['bad_if'][] = virtual-;
$config['bad_if_regexp'][] = /serial[0-9]:/;
$config['bad_if'][] = loopback;
$config['bad_if'][] = lo;
$config['bad_if'][] = dummy;
$config['bad_if_regexp'][] = /tunnel_[0-9]/;
$config['bad_iftype'][] = voiceEncap;

Other Configuration Options

A few other customizations in the /opt/observium/config.php file.

$config['rrdgraph_real_95th'] = TRUE;
$config['allow_unauth_graphs']    = 1;
$config['login_message']    = Unauthorised access shall render the user liable to criminal and/or civil prosecution.;
$config['page_title_prefix'] = Rich Kreider - Monitoring :: ;