Network cards and achieved throughput

Dr. Z · 07-03-2007, 23:42

Here at uni I run a little network and I have a few little niggles that keep cropping up that I think can be put down to my network cards but I am not sure.

Omitting all of the AD, DNS, DHCP, Level 2 management and all that stuff, basically I have a windows-based server box which has a few shares that are accessible from any of 10 client PCs. At any one time, the server has a load of around 300kbps but at "busy" times this can sit at 1-2mbps for sustained periods - all of this is no problem at all.

The real problem comes whenever peak/burst speeds are required (biggish data transfers). I expected my gigabit lan to have a sustained throughput of somewhere in the region of 30-40mpbs worst case (my drives can sustain high 70s/low 80s individually but I have a striped set array and a mirror in operation). However, I only actually get peaks of around 18mpbs and a sustained average of closer to 13-14mpbs.

I have tried a lot of things, including moving to a (well configured) linux/samba based configuration but it just doesnt seem to make much difference - is this down to my network cards? In the server machine I have a pair of D-Link DGE-530Ts which I expected to run fine. I swapped one of these with a Netgear GA-311 to no noticeable difference.

I am at the end of my list of things it could be. I dont really want to splash out on something like an Intel Pro/1000 for each of my machines that needs the throughput because it will mount up!

What cards are a good tradeoff between actual throughput and cost? Have I missed a setting or something that is causing a bottleneck? I am using a Netgear 8-port gigabit switch and although removing it didnt make any difference could it have its own small part to play? I dont know, I am totally lost as to why everything is so slow!

Will · 08-03-2007, 09:21

Have you tried Linux -> Linux copying? I'm just wondering if it's some funny windows buffer/relay packet service thing that's causing delays? Driver issues? I'm better at diagnosing switch problems than NIC problems really

When you said you moved to a linux/samba box is this running on the same box with the same hardware?

Mark · 08-03-2007, 09:44

Aye, I do know Windows has throughput issues, though right now they're more common with Vista due to Microsoft's new driver model.

There's a lot of stuff that's broken thanks to the new driver model (e.g. video hardware overlays).

Daz · 08-03-2007, 10:20

What switch are you using DRZ?

Dr. Z · 08-03-2007, 18:05

Yes I have tried Linux -> Linux (which was actually slower!!) and win2k3 -> win2k3.

The switch I am using between my PCs is a GS608 v2, the ones upstairs i cant remember the model numbers of but they are 48 port 100mpbs jobbies with two gigabit ports and two fibre port bays.

mejinks · 09-03-2007, 00:13

cabling?

07-03-2007, 23:42	#1
Dr. Z I'm going for a scuttle... Join Date: Jul 2006 Posts: 2,021	Network cards and achieved throughput Here at uni I run a little network and I have a few little niggles that keep cropping up that I think can be put down to my network cards but I am not sure. Omitting all of the AD, DNS, DHCP, Level 2 management and all that stuff, basically I have a windows-based server box which has a few shares that are accessible from any of 10 client PCs. At any one time, the server has a load of around 300kbps but at "busy" times this can sit at 1-2mbps for sustained periods - all of this is no problem at all. The real problem comes whenever peak/burst speeds are required (biggish data transfers). I expected my gigabit lan to have a sustained throughput of somewhere in the region of 30-40mpbs worst case (my drives can sustain high 70s/low 80s individually but I have a striped set array and a mirror in operation). However, I only actually get peaks of around 18mpbs and a sustained average of closer to 13-14mpbs. I have tried a lot of things, including moving to a (well configured) linux/samba based configuration but it just doesnt seem to make much difference - is this down to my network cards? In the server machine I have a pair of D-Link DGE-530Ts which I expected to run fine. I swapped one of these with a Netgear GA-311 to no noticeable difference. I am at the end of my list of things it could be. I dont really want to splash out on something like an Intel Pro/1000 for each of my machines that needs the throughput because it will mount up! What cards are a good tradeoff between actual throughput and cost? Have I missed a setting or something that is causing a bottleneck? I am using a Netgear 8-port gigabit switch and although removing it didnt make any difference could it have its own small part to play? I dont know, I am totally lost as to why everything is so slow! __________________

08-03-2007, 09:21	#2
Will BBx woz 'ere :P Join Date: Jan 1970 Posts: 2,147,487,208	Have you tried Linux -> Linux copying? I'm just wondering if it's some funny windows buffer/relay packet service thing that's causing delays? Driver issues? I'm better at diagnosing switch problems than NIC problems really When you said you moved to a linux/samba box is this running on the same box with the same hardware? __________________ *No No!*

08-03-2007, 10:20	#4
Daz The Stig Join Date: Jun 2006 Location: Swad! Posts: 10,713	What switch are you using DRZ? __________________ apt-get moo

08-03-2007, 18:05	#5
Dr. Z I'm going for a scuttle... Join Date: Jul 2006 Posts: 2,021	Yes I have tried Linux -> Linux (which was actually slower!!) and win2k3 -> win2k3. The switch I am using between my PCs is a GS608 v2, the ones upstairs i cant remember the model numbers of but they are 48 port 100mpbs jobbies with two gigabit ports and two fibre port bays. __________________

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08-03-2007, 09:44	#3
Mark Screaming Orgasm Join Date: Jul 2006 Location: Newbury Posts: 15,194	Aye, I do know Windows has throughput issues, though right now they're more common with Vista due to Microsoft's new driver model. There's a lot of stuff that's broken thanks to the new driver model (e.g. video hardware overlays).