Scott Mueller's Upgrading and Repairing Forum

Hi Scott,

I have a NSLU2 up and running connected to my home network. I have a single hard drive connected to it - a WD Caviar Green 1TB SATA drive in an external USB2 enclosure formatted as EXT3.

I am currently in the process of backing up everything off of my main storage drive (2 x Seagate 1TB ES.2 in RAID 1) on my Quad core Windows 7 PC. Basically the throughput is extremely slow, it has been running for several days (so far) backing up 293GB of music and photos etc.

I understand the bottleneck in this setup is the 100Mbit ethernet port on the NSLU2 but theoretically that would permit 11.6MB/s (at least according to this site), I am seeing speeds between 1 and 2 MB/s with the device when copying over this data.

Do you happen to know why the throughput would be this low? Is the processing power of the NSLU2 (266Mhz) degrading speeds significantly?

Thanks in advance for any info!

-Paul

Sounds like par for the course. Cheap NAS devices typically have horrible read/write performance. As a performance test, try this: Download and install the Windows Resource Kit tools, which includes the NTIMER and CREATFIL commands. Then open a command prompt, navigate to a mapped drive on your NSLU2, and run the following command:

ntimer creatfil test1.dat 97657

This will show the amount of time it takes to write a 100,000,768 byte (approx. 100MB) file called test1.dat directly from memory to the drive. Divide 100 by the number of seconds it took (ETime), and you will know the write performance in MBps. For example, if it took 20 seconds, then the calculation would be 100MB / 20 seconds = 5 MBps

To determine the read performance, run the following command:

ntimer xcopy test1.dat c:\temp

This will show the amount of time it takes to copy the test1.dat file you just created on the network drive to the temp folder on your boot drive. Then just as before, divide 100 by the number of seconds it took, and you will know the read performance in MBps.

Let me know what numbers you get for those tests. I seem to remember getting between 2 and 5 MBps on those tests using an NSLU2. But don't feel bad, the NSLU2 was actually slightly *faster* than a WDC My Book World Edition II I tested, even though the latter was connected via *gigabit* Ethernet.

If you want to test using a larger 1GB file, change the number in the creatfil command to 976563 and then divide 1000 by the number of seconds the write and read operations take.

While cheap NAS drives are good for many uses, you can get up to 5 times (or more) faster performance using an old discarded Pentium III or 4 PC (running the "free" Windows XP that came with it) as a server/NAS device. If you use a newer/faster PC the difference will be even greater. Scott.

Hi Scott,

thanks for the response. Here are the results of my test:

Write speed: 2 MBps
Read speed: 4.5 MBps

So my backup seems to be in the expected zone as far as performance is concerned.

Why are some of these NAS units so slow? is it to do with how fast or slow the controller inside them runs? what distinguishes a home made "leftover PC" NAS as far as speed goes?, CPU, memory?

Very interesting

-Paul

The performance is dictated by everything between the network connection and the drive itself. Basically that means it could be the internal controller, drive interface, network interface, or anything in-between.


The slowest PC that can run XP, if equipped with a gigabit Ethernet connection will out-perform most cheap NAS devices by at least 4 or 5 times. A faster PC with fast SATA drives will perform even better, up to say around 100MBps assuming the drives are not the bottleneck (e.g. SATA drives in a RAID configuration).

Here's a tip: When I used an NSLU2 as a music server I had 400GB of MP3 files, which would have taken nearly 3 *days* to load, IF going through the NSLU2. Instead I connected the drive directly to my system and loaded it in only 3 *hours*. To do this I took the EXT3 formatted drive that was attached to the NSLU2, connected it directly to my system via eSATA, and used the Ext2 Installable File System for Windows to allow me to access it directly under Windows. Scott.

Thanks Scott, I'd actually thought of the same idea but was too lazy to stop the backup <g> It finally completed in *only* 2.5 days. I did the same backup to an eSata connected 2.5" drive and it completed in less than an hour if I remember correctly.

400GB of MP3's! Wow, that is a LOT of music
How did you setup your NSLU2 to be a music server?

I just put it on the network with the music drive shared, pretty much the same as my current server. With the music shared I can play any of it on any PCs (using Winamp, which handles large media libraries much better than Windows Media Player) or Sonos ZonePlayers. Scott.