DIY Atom-based NAS odd test results

[trafficone]

Hi,

I'm building a NAS on a D945GCLF2.
*running Openfiler
*1GB Ram
*using onboard NIC
*SATA 80GB HDD

I've run iozone on it from my Macbook with a 2.2GHz processor, and 2GB RAM across a 1000 Mb/s link.

My question is that my test results show a consistent write speed of 11MB/s, which is somewhat slow. However, my read speeds exceed 1.5GB/s! An excess of the line speed. I want to know what could be causing this? How could I possibly rectify this? And, if there's time, how could I improve my write speed?

Thanks in advance!

 

[thiggins]

What is your iozone command line? Is the MacBook running Mac OS or Windows?

What throughput do you get when you do a drag and drop filecopy?

Upload the wks file and I'll have a look.

 

[trafficone]

Command is:
iozone -Rab realtest.xls -i 0 -i 1 -+u -f /Volumes/Moo/Rhino -q 64k -n 32M -g 2G -z

The Macbook is running MacOS.

I don't know what a wks file is, but you can have my results in this .xls file.

 

[thiggins]

Thanks for the iozone results.

Your write speeds are being limited by the onboard 10/100 Mbps NIC.

Anytime you see speed greater than your LAN connection, it is due to caching in the NAS, OS or both. Note that once you hit 512 MB file size, read speed drops to about the same as write, i.e. around 11 MB/s, just shy of the 12.5 MB/s maximum that a 100 Mbps LAN connection can deliver.

Bottom line. To take full advantage of the Atom, you need to add a gigabit Ethernet NIC.

 

[trafficone]

The Little Falls 2 has an on-board gigabit NIC, that and the dual-core 330 are why I chose it over the Little Falls 1.
From the horse's mouth:
http://www.intel.com/products/desktop/motherboards/D945gclf2/D945gclf2-overview.htm

I am running the connection through a gigabit switch, so I don't think that that is where my problem is.

I do think its worthwhile to point out to anyone trying to repeat what I'm doing that Openfiler comes default with the buggy r8169 driver (it produces non-existent dropped packets), but to run it on the D945gclf2, you will need to to install the r8168 driver. Hope that helps anyone.

 

[thiggins]

Sorry for not noticing the different Atom board.

The 11 MB/s speed is a pretty definite indication of 100 Mbps LAN connection. So maybe the R8169 driver is doing more (or less) than dropping packets.

 

[trafficone]

No problem, that was still a good catch, I went through the whole line and found I was running it through a 10/100 switch, here are my new numbers:

Auto Mode
CPU utilization Resolution = 0.000 seconds.
CPU utilization Excel chart enabled
Record Size 64 KB
Using minimum file size of 32768 kilobytes.
Using maximum file size of 2097152 kilobytes.
Cross over of record size disabled.
Command line used: iozone -Rab realtest.xls -i 0 -i 1 -+u -f /Volumes/192.168.1.192/file -r 64k -n 32M -g 2G -z
Output is in Kbytes/sec
Time Resolution = 0.000001 seconds.
Processor cache size set to 1024 Kbytes.
Processor cache line size set to 32 bytes.
File stride size set to 17 * record size.
random random bkwd record stride
KB reclen write rewrite read reread read write read rewrite read fwrite frewrite fread freread
32768 64 45069 46119 1545946 1679201
65536 64 41677 42240 1159970 1257212
131072 64 37300 40155 1572794 1687113
262144 64 36825 34969 1550158 1629812
524288 64 32280 34629 34233 34536
1048576 64 28387 25679 27824 27253
2097152 64 20819 25444 28330 27820

My test results were considerably worse with the r8169 driver.

 

[thiggins]

Those numbers are more like what I would expect. Interesting that you still see most of the caching on reads. Could be an openfiler thing.

 

[trafficone]

Good to hear, thanks!
Whereabout on the list of tested NAS's might mine be?
Also, I noticed in your tests of the Intel D945GCLF that the write speeds were higher than this, what do you think might cause that?

 

[thiggins]

Good to hear, thanks!
Whereabout on the list of tested NAS's might mine be?
Also, I noticed in your tests of the Intel D945GCLF that the write speeds were higher than this, what do you think might cause that?

You'll have to judge for yourself where your NAS fits on the charts. The Wind PC and Artigo 2000 NASes are both there.

My guess is that Ubuntu server is the difference. I found it to have the highest performance of any of the distros I have tried. See this page (down near the bottom) for a comparison plot of Openfiler and Ubuntu on the Atom.

 

[eon]

Build your own

Trafficone,

What is your drive/raid setup, I only noticed a 80Gb listed. If you are now running at gigE speed and it is only one drive that may be the capability of the one drive.

The little falls 2 is a very good board and can run EON + ZFS in 32 or 64-bits (opensolaris) if you are not attached to openfiler give it a twirl.

http://eonstorage.blogspot.com/
http://eonstorage.blogspot.com/2009/01/eon-0589-based-on-snv104-is-released.html