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Q Prickly display issue Is there something I can use to collect all my LAN data/network/disk space information into a dashboard? I have several computers running (including virtual machines) and I want to send their data to a dedicated server that will show me all the information on one screen.

Derrick Long

A There are a number of ways of collecting this information, depending on what you want to do with it. Based on your brief description of your needs, Cacti (www.cacti.net) would seem to be a good fit. Cacti is a web application, so you’ll need a web server such as Apache installed on one computer on your network, then install Cacti on that. This can be done by downloading a tarball from the web site, or there may be a package for your distro. Using Cacti, or any other web application, means you have the extra work of setting up a web server if you don’t already have one. On the plus side, it also means that Cacti’s information is then available on any computer on your network, requiring only a web browser.

The other requirement is that you have the SNMP daemon (see boxout, overleaf) installed and running on each computer you want to monitor. Depending on your distro, this may already be the case. Otherwise, install the relevant package – snmpd for Ubuntu and friends. When you first access the Cacti page on your server, it’ll walk you though some basic setup. Then you can start adding information. Cacti collects information from your computers and stores it in a database, which it can then display in the form of graphs. First you add a device, a computer you want to monitor, then you can pick and choose the items you want to graph.

The first tab on the Cacti home page is the console where you do all of this. The next tab is where the graphs are displayed. You can set up different collections (or trees) of graphs, depending on the information you need. You could have a separate tree for each computer, displaying various aspects of that computer. Or you could have, say, a CPU load tree that shows that information for each computer on the network. This enables you to customise the display according to your current needs.

Because all the hard work is done by Cacti, adding another device is as simple as making sure snmpd is running on it and adding the graphs you want.