The PRTG software has a few licencing levels, one of which is a free 3o sensor licence. Not a free time limited demo, a free forever licence.
30 sensors might sound like a small amount when you find out what a sesnor is…
The licensing options are based on the number of sensors (not on the number of devices or IPs). We define one (1) sensor as any particular, individual monitoring entity. One sensor monitors one network service, one URL, one network connection, one port of a switch, one NetFlow export stream, one CPU load, one disk drive, etc. Please have a look at the list of supported sensor types. Monitoring one item from this list counts as one sensor.
Taken From http://www.paessler.com/support/faqs#e1913
…however, I find that 30 is enough for what I want to monitor on my network. There are some sensors that “bundle” more that one metric into them. I could use more if I had them though 🙂
Network Port Monitoring
For example: monitoring a single network port counts as one sensor, but that port could return several metrics. The HP switch I use returns the following information: Downtime, Transmitted, Packets, Broadcast Packets, Multicast Packets, CRC Errors, Undersize Packets, Oversize Packets, Fragments, Jabbers, Collisions, Packets <= 64 Byte, Packets 65 – 127 Bytes, Packets 128 – 255 Bytes, Packets 256 – 511 Bytes, Packets 512 – 1023 Bytes, Packets 1024 – 1518 Bytes, Drop Events.
That’s a lot of information from one sensor, but expected for a network port.
ESX Performance Monitoring
Another type of “bundled” sensor is the ESX Performance Monitoring one. This gives much more useful and varied information: CPU usage, Datastore total ReadLatency, Datastore total WriteLatency, Disk read, Disk usage, Disk write, disk.deviceLatency, disk.kernelLatency, Downtime, Memory active, Memory consumed, Memory consumed, Memory swap used, Network received, Network transmitted, Network usage, Power
This is a varied collection of useful information, all collected in one sensor. It covers the four main metrics: CPU, Memory, Disk, Network. All of these metrics are available in graph form too, so you can see the history of this information over various time periods, from as little as the last two hours, up to a year ago.
You don’t even need to see all these metrics either. If you are not interested in the “Power” metric for example, a few clicks later and it’s gone from all your graphs. The data is still being collected, just not shown to you.
My Home Network Monitoring
I use it on my home network to monitor and graph the throughput of my internet router, my wireless router, and my Synology Diskstation 1813+ NAS. I also have monitors for my three NUC ESXi hosts.
With all the data, this tool collects, you might think it’s hard to find what you are looking for, or just want a way of displaying the data to make it easier to look at. For this, PRTG has Network Maps. Below is my network map for my home network…
The data shown in the graphs are updated every 30 seconds or so (depending on your settings). You can see that one of my ESXi hosts is offline at the moment, and that some of my critical virtual machines are listed.
The network map layout can be in almost any layout you can think of. It doesn’t have to be as pretty as mine.