MSI Wind PC NAS - Transfer Rate / Performance Issue

[jgotsch]

Hello,

I've followed Tim's "Build Your Own Atom-based NAS" article to build a RAID-1 NAS based on the MSI Wind PC. Thanks for the great article!

Following is a list of the components I used to build my NAS:

- ATI WindPC (Intel 1.6GHZ Atom, 945GC/ICH7, 2GB DDR2 533/400 MHz Memory, Realtek 8111C 10/100/1000Mbps)

- Western Digital Caviar Green 1TB, 32MB Cache, 7200 RPM SATA II (x2)

- Kingston KVR667D2S5/2G 2GB 667MHz DDR2 Non-ECC CL5 SODIMM ValueRam Memory

- 4GB SanDisk Ultra II Compact Flash Card

With all the components assembled, I followed the instructions to install Ubuntu 9.04 server, along with Samba, MDADM and Webmin onto the 4GB SanDisk. I also followed the instructions to use Webmin to format the hard drives (ext3) and configure the RAID-1 array, create the mount points and read/write permissions...etc. Everything went smoothly and I was able to mount the NAS from my Ubuntu 9.04 desktop machine.

As a test, I copied over a single 2 MB file to the NAS and then deleted it. Everything was looking good. Then I decided I would copy about 5GB of data to the NAS. When the file transfer started I think the sustained transfer rate was around 2MB/sec, which seems slow as I was expecting more like 20-40MB/sec. However, after about 30 seconds to a minute the transfer rate began steadily dropping to 600KB/sec. Then the transfer rate dropped further until it did not appear that any data was being copied at all, although the "file transfer" status window stayed up. Even the hard drive lights on the NAS had stopped flashing. All total, about 600MB of data was copied to the NAS.

Has anyone had a similar experience, or have any suggestions what might be going on? Is this some sort of caching issue? Are there some configuration parameters I need to tweak? Is it my hardware? Not sure where to begin trouble shooting this. All help is appreciated!

 

[roamer]

Hello,

I build a similar configuration after read this nice article about Ubuntu on Atom-platform.

My config:

Intel D945GCLF2 board (with Realtek 8111C onboard)
2x 1TB WD EADS hdd as mirror
2 GB RAM
4GB CompactFlash for Ubuntu
and Ubuntu 8.10 server

The write performance from a PC with Vista (core2duo,4GB RAM) was between 50-60 MB/s with a bigfile (>2,5GB).



- Have you tested the speed with ftp instead of samba ?

- login on your nas and start the 'top' tool during the file transfer
is there any process that is consumpting a lot of CPU or RAM resources?

-Are you disks in the nas are ok - can you locally on the nas copy such big files from one directory to another?

 

[jgotsch]

Hi roamer,

I will try the tests you suggested and report back here.

Jason

 

[roamer]

You should also check on your NAS the logfiles in the directory /var/log for errors. Especially in the messages files.

 

[jgotsch]

- Have you tested the speed with ftp instead of samba ?
Is FTP enabled by default or do I need to enable and turn the service on? I wasn't able to test this.

- login on your nas and start the 'top' tool during the file transfer
is there any process that is consumpting a lot of CPU or RAM resources?
I observed the running processes and didn't note any consuming an unusual amount of resources.

-Are you disks in the nas are ok - can you locally on the nas copy such big files from one directory to another? I was able to copy about 600MB of data to the NAS (noted in a previous post) and I was able to locally copy this data to another directory on the NAS without any problems.

Additionally, I did some googling on the issue and it seems like the Realtek 8111c NIC has/had driver stability issues on Linux. Since Ubuntu is still pretty new I haven't been able to confirm if Ubuntu 9.04 successfully incorporated the fix. If the driver only become unstable under heavy loads, it could be difficult to pin down as the driver would appear to work fine for casual users.

Additionally, I discovered that the FreeBSD community had recently incorporated a patch for the Realtek 8111c. I've heard good things about FreeNAS (based on FreeBSD), I decided to take it for a spin. I was able to successfully transfer all 50GB of data using FreeNAS but file transfer speeds still maxed out at 1.6MB/sec. My NAS box is connected to a Linksys WRT54G router, which is 10/100 ethernet. And I am transferring data from my desktop machine over a wireless network, not a wired connection. So I guess these two factors may slow things down. But does 1.6MB/sec sound right? I'm at work now but I intend to try connecting my desktop machine directly to one of the router ports and see if I can achieve a better transfer rate.

Jason

 

[roamer]

- Have you tested the speed with ftp instead of samba ?
Is FTP enabled by default or do I need to enable and turn the service on? I wasn't able to test this.

Oh sorry, yes I have installed pureftpd manually via webmin.

Additionally, I did some googling on the issue and it seems like the Realtek 8111c NIC has/had driver stability issues on Linux. Since Ubuntu is still pretty new I haven't been able to confirm if Ubuntu 9.04 successfully incorporated the fix. If the driver only become unstable under heavy loads, it could be difficult to pin down as the driver would appear to work fine for casual users.

As far as I remember it was a problem with 64bit version of Version 8.04.
But anyway I have used 32bit version of 8.10

Here has another user made some tests, which also pointing out that performance of 32bit linux is better than 64bit.
http://forums.smallnetbuilder.com/showpost.php?p=9472&postcount=33

Additionally, I discovered that the FreeBSD community had recently incorporated a patch for the Realtek 8111c. I've heard good things about FreeNAS (based on FreeBSD), I decided to take it for a spin. I was able to successfully transfer all 50GB of data using FreeNAS but file transfer speeds still maxed out at 1.6MB/sec. My NAS box is connected to a Linksys WRT54G router, which is 10/100 ethernet. And I am transferring data from my desktop machine over a wireless network, not a wired connection. So I guess these two factors may slow things down. But does 1.6MB/sec sound right? I'm at work now but I intend to try connecting my desktop machine directly to one of the router ports and see if I can achieve a better transfer rate.

Jason

I have tested Opensolaris and FreeNAS before I decided to go ahead with Ubuntu.

FreeNAS 0.7 was my first choice
Pro:
- Easy Installation and setup on CompactFlash
- ZFS is implemented

Con:
- poor performance
--> out of the box only around 20MB/s write

Opensolaris 2008/11
Pro
-> easy to configure a raid only with few shell commands
-> very good performance

Con:
- to install a complete OS with gnome on a CompactFlash may be not the best solution.
- no webbased config, no add-on like lm-sensors, smartctrl, ...

As I made some tests with FreeNAS, I recognized that the system freezed, if I pulled out a disk of the raid1 during a filetransfer...
I made the same with Ubuntu and the NAS was running, it takes a while until I received a mail about the failed disk, but the system was still running.

As far as FreeNAS has implemented ZFS v13 (FreeBSD 8) , I will test it again...