Half a Page of Scribbled Linux

In my last post about network speed, I realize there’s another variable in the loop–disk access. One of the machines is a very old Dell Dimension XPS T600. To remedy that, I needed a test that doesn’t rely on disk.

First I tried netio. The server side ran, but the client complained there was no route to the server host. I tried unsuccessfully using both the TCP and UDP modes before moving on.

Next, I tried iperf. What’s nice is that it’s part of the standard distribution in Ubuntu and Fedora. The result was throughput between the PCs connected via Ethernet to the Actiontec router is about 70 Mbps. Both machines have 10/100 cards in them, so I’m no longer worried about the router being a bottleneck.

There are two gotchas I found when installing Windows 2000 Server on VirtualBox on my Ubuntu 10.04 LTS desktop. The first is that the disk name can’t have a space. I can’t say if this is still an issue with current versions of VirtualBox, because making a new VM without a space in the name didn’t fix my problem, which was that the Windows 2000 installation would restart itself over and over. It would get to the component selection, then copy files and reboot.

What did fix the problem was a start-up message:
[ 15.482935] vboxdrv: Warning: 2.6.31+ kernel detected. Most likely the hardware performance
[ 15.482937] vboxdrv: counter framework which can generate NMIs is active. You have to prevent
[ 15.482938] vboxdrv: the usage of hardware performance counters by
[ 15.482939] vboxdrv: echo 2 > /proc/sys/kernel/perf_counter_paranoid

Although /proc/sys/kernel/perf_counter_paranoid doesn’t exist on my system, /proc/sys/kernel/perf_event_paranoid does and running echo 2 > /proc/sys/kernel/perf_event_paranoid stopped the looping installation problem.

In pursuit of cutting the cable TV cord, I need to have ethernet available to all TVs in the house. Right now, there’s 802.11g WiFi and Coax. You can use FiOS’ coax as a LAN with a MOCA bridge, but you’ll need either a dedicated MOCA bridge (~$70) or a used ActionTec router. Another option is to run Ethernet cable through the house–something I’d rather avoid if I can. So the question is, how much bandwidth do I need? According to the Wikipedia artlcle on HD video 1080p needs between 3.5 and 8.25 Mbits/sec, depending on the source.

To test my existing connections, I first did a speed test (Broadband Blue Angles (4MB) from the closest provider) of my FiOS connection on my desktop connected directly to the FiOS router. The speed varies between 6 and 7.5 Mbits/sec. This is enough for most streaming. But what about if I’m connected via WiFi? The same test from my laptop connected to the FiOS router over WiFi yeilds about the same result. So WiFi isn’t limiting my Internet speed.

Lastly, I want to know how much bandwidth I have internally to use a Myth TV box that’s not streaming from the Internet. To do this, I set up a random 100MB file:
$ dd if=/dev/urandom of=100MB.bin bs=1M count=100
to transfer around. Across two boxes over a wired FiOS connection I got only 4-5.5MB/sec. Between one wired and one WiFi box I got 2-2.5 MB/sec. This would seem to indicate the ActionTec router is limiting my intranet speed.