So my SheevaPlug was up and running for months and the disc connected to the USB port is fed with my audio and video collection. As written in my previous blog post, last weekend my plug died, as the PSU went up in smoke. I hope this is only due to the PSU and a new one is already in the mail. Hopefully, the Sheevaplug will be up and running again by next weekend.
Meanwhile I found this unfinished blog post on performance measurement back from spring. It is incomplete as there are no measurements on local and network speed but I guess it is worthwhile sending it out into the net when keeping those three drawbacks in mind.
So, while the handling (i.e. mostly meaning copying files) ‚feels‘ quite ok over my new all-GigaBit network setup, where both my laptop, which has a Realtek Gigabit Ethernet controller, and the SheevaPlug are connected to a TP-LINK 5 Port
Now, I am curious where I am located in the NAS-speed-charts and so some hard numbers are needed.
First I checked if somebody else already did some performance evaluation of the SheevaPlug. The only source I found is Kenny’s computingplugs.com Wiki-entry, the collective results of his performance tests on the SheevaPlug.
After I did the measurements I also located Christoph Handel’s Benchmark but he has a slightly different setup with a newer kernel version involved.
So what I tried to do back then on my Plug is to verify the NFS performance with what Kenny measured. But let’s have some technical details first:
My SheevaPlug at the time of testing runs
- 2.6.30-2-kirkwood #1 Sun Sep 27 22:57:55 UTC 2009 armv5tel GNU/Linux
- nfs-kernel-server Debian
Package at version 1:1.2.0-4.1
- NFS Protocol Version 4 is used
A file is created of exactly the size that Kenny used in his tests with
dd if=/dev/zero of=bigfile bs=10 count=109512817 and the time is measured for copying back and forth between a client and the SheevaPlug.
Here are the results wrapped up in a similar table to Kenny’s with my measurements filled in:
|From Sheeva Plug to computer||88.094 sec||75.009 sec||73.397 sec||78.833 sec||13.892 MBytes/sec|
|From computer to Sheeva Plug||85.451 sec||74.585 sec||76.727 sec||78.921 sec||13.876 MBytes/sec|
The SheevaPlug is running between 40% and 60% CPU load (nfsd) during the cp operation.
So my measurements are quite inline with Kenny’s. Just CPU usage is much lower than measured under his trials.
When comparing this to the GigaBit Ethernet File Copy write performance NAS Charts over at SmallNetBuilder, performance doesn’t look too good for the SheevaPlug. Furthermore, Christoph’s speed tests suggest that you can at least have 10 MB/s more both in up- and downlink via NFS.
I’m just wondering what the limiting factor is here. USB 2.0 bandwidth shouldn’t be the problem and it seems that the Kirkwood CPU as well has not reached it’s limit yet.
I guess I have to repeat my measurements once the Plug is up and running again. But if anybody
has a clue why NFS is so slow, go ahead, point it out in the comment section.