NFS over openVPN – Part 2

Well, it wasn’t suppose to be that easy……

Getting some very mixed results.. it’s was time to get back on the test bench.
Playing around with iperf I knew that OpenVPN tunnel should be able to push enough bandwidth. Guess it was time to play around with the NFS options again…

Since I’m only interested in read speed, this is the only thing I tested.
To make variation in latency for the different test, I used only a 16MB file for testing.

Test command:

mount_nfs -o rsize=$rsize,vers=4.0alpha,ro,async,noatime $HOST://$RM /$LM
dd if=/path/to/testfile of=/dev/null bs=16k
umount /$L_mount
sleep 10

$rsize= rsize for testing (default, 1024,2048,4096,8192)
$HOST = NFS HOST
$RM = Remote NFS Mount Point
$LM = Local NFS Mount Point

Test run on a 30min interval and was doing during the night.

Initial conclusion is that I need to change my `rsize`… Will do some more testing during daytime, to see if variation in latency (usually more variation and bigger during day..) will effect the performance (it should do, but the best rsize will hopefully be the same….

It might be time to change out my low end router, a Linksys WRT54GL, witch is place between the client and internet. As you can see from the graph bellow the load is quite heavy.

I’ve been doing quite some testing earlier that evening, but you can clearly see the spikes in load when the test is do. Check the intervals just after midnight..

***UPDATE ***
Done some more testing, and here are the results

After first test, I could easily scrap 1024 and STD. But it was a close call with high rsize. It was time to check if even high size would matter.

In the second test, I also created a bigger testfile. Since the variation in speed and latency where to big to make a final conclusion.

The third test, I added yet a higher rsize. But as the results shows, I had found the highest already. When using 16384 the read speed slowed down again…..

Conclusion
mount_nfs -o rsize=12288,vers=4.0alpha,ro,async,noatime 192.168.0.1://media /mnt/media/

It’s a close call between 12288 and 8192… Not sure what is best… I’ll start using 12288 as it is slightly better on average…. Maybe I’ll do a intense test on only these to values on a later point….

Leave a Comments