TomatoUSB + Optware + rrdtool + dygraphs = cool bandwidth monitor

04 February 2012 2 minutes

I recently upgraded my Buffalo WHR-HP-G54 to an ASUS RT-N16 as I needed gigabit ethernet; and usb ports + wifi N are all welcoming upgrades to the aging buffalo. As an inevitability, I installed TomatoUSB and plugged in a 4GB USB stick. Now, TomatoUSB itself is a very good system with loads of features but you can extend even more by adding Optware. I will not go into the installation as there already is a very good guide to follow.

Once you have the USB stick mounted and Optware up and running, you can do lots of nifty things. For example, I installed zsh, screen, vim and a whole bunch of other essential stuff. A few examples can be found here.

One particular interest I had when found out about optware was the extension of tomato’s visual bandwidth log graphs. I said extension because the original one comes with tomato has a max 24 hour window. However, occasionally I want to see what happened in the previous week or even month. So first, I thought of rrdtool and rrdgraph. Now rrdtool is a good database for this purpose, however rrdgraph proved to be too resource intensive for the little cpu.

So I searched around and found dygraphs. This is a perfect solution as all you need is to feed the data in csv format and the graphing would be done on the client’s browser. Have a look at my example here (1 week window), you can click&drag the cursor to zoom in and double click to zoom out.

Cool? If you’re interested, let’s start. Assuming you already have a persistent storage (jffs,usb/sd card, etc.) setup at /opt, first, ssh to your router, then:

ipkg update
ipkg install perl rrdtool
wget -O /opt/bin/
chmod +x /opt/bin/
cru a bwlog "*/1 * * * * /opt/bin/"

That will install rrdtool, perl and download my rrdtool collector script, put it in the crontab to be executed every 1 minute. Now, create a directory somewhere in your /opt to store the necessary files, mine is at /opt/share/www/cgi-bin.


wget -O bandwidth.cgi
chmod 755 bandwidth.cgi
chmod 644 dygraph-combined.js
rm -rf /tmp/var/wwwext/cgi-bin
ln -s /opt/share/www/cgi-bin /tmp/var/wwwext/.

You should also append the these into /opt/.autorun. This will tell tomato to run these command right after mounting my usb stick.

echo 'cru a bwlog "*/1 * * * * /opt/bin/"' >> /opt/.autorun.
echo 'rm -rf /tmp/var/wwwext/cgi-bin' >> /opt/.autorun
echo 'ln -s /opt/share/www/cgi-bin /tmp/var/wwwext/.' >> /opt/.autorun

What just happened is we got the files we need, save them somewhere that will not disappear as the router restart, link them to the router’s cgi-bin directory. Now, assuming the router’s ip is, you can test everything by going to: there you should already see a few data points collected by earlier. Download some big files, leave it running for a while (the page will auto refresh every minute) and you should see more pretty data come up :)


WHR-HP-G54 and SD card mod

I just got a Buffalo wireless router WHR-HP-G54 a few days ago. It’s small, covers a good range (has a built-in internal amplifier), has decent memory 4MB ROM/16MB RAM and it can be modded to have an sd/mmc card for storage.


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