Identifying slow LAN transfer speeds

Headcase_Fargone

Limp Gawd
Joined
Mar 25, 2010
Messages
284
So I recently built a little Atom-based media server to serve up movies and music to my TVs and phone. I went with this board which was the lowest power solution I could find. In it I have two Samsung "Ecogreen" 5400rpm HDs and a 2GB SO-DIMM.

I'm running Ubuntu 10.04 and everything is going swimmingly except for one nagging issue. Transfer speeds to/from other devices on the LAN are a little on the slow side, capping out right at 20MB/s. By comparison, I typically see about 50MB/s pulling files from the same machine on my big gaming rig. Now, I'm not expecting the same transfer rates on a mini-ITX Atom board as I'm getting on a machine with 6GB of RAM, an i7 CPU and an SSD. But less than half seems a little hard to swallow.

Is there an easy way to track down what the bottleneck might be?

In case it helps, this is the entire configuration:

Intel D945GSEJT with Atom N270 CPU
2GB DDR2 533MHZ
4GB Kingston 133x CompactFlash -> IDE adapter, primary OS installation
2x 1.5TB Samsung F2 HD154UI Ecogreen HDDs

Connected to Netgear WNDR3700 router with built-in gigabit switch with store-bought CAT6 cable.

Transferring from an old P4 2.4GHZ (also running Ubuntu) and an old 7200rpm HDD. I would have thought this was the bottleneck if anything, but I get 50MB/s to my gaming rig from it.
 

stiltner

[H]F Junkie
Joined
Mar 16, 2000
Messages
10,686
Verify latest drivers from Realtek would be my first suggestion.

Handling 20mbit is not anything that a 386 couldn't handle, more or less the Atom. Its not a CPU bottlenecking issue, thats a guarantee. Once I verified I had the latest drivers, I would try and eliminate the other bottlenecks.

Your 133x speed CF card troubles me for many reasons. It has the potential in the IDE / CF adapter to be a bottleneck because of just a funky interface chip that could be some cheap crap.

The Sata drives aren't an issue either, they're more than capable of pumping that volume. I'd suggest you verify the drivers, and then verify the CF card. Other than that, you have USB ports, try a USB to 10/100 dongle setup? Here, for under $5 you can snag one:

http://www.dealextreme.com/details.dx/sku.2797 I dunno what its quality is, but for testing, it does give you a hardware based bottleneck remover in a sense. It might be worth considering for the money, but it'll take a good 3-4 weeks to arrive from Hong Kong so be prepared to wait
 

Headcase_Fargone

Limp Gawd
Joined
Mar 25, 2010
Messages
284
Interestingly enough, I just tried transferring a large amount of data from afore-mentioned gaming rig to the new server. It's transferring right this instant at 70MB/s. That's megabytes, not megabits. Same type of files I was transferring from the old P4 at that. I did change MTU from automatic to 9000. Do jumbo frames make that huge of a difference?

I'll have to try transferring some more files from the P4 tomorrow just out of curiosity.

As for the CF card, the OS is installed on it and is running very snappy so far. My only concern with it is time to failure from being written to too often. I've installed Ramlog and set noatime in fstab to mitigate that though.
 
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