Slow network connection

[Will]

Hi all,

I've been copying a lot of files around on my network recently and I'm a little confused.

I've got a 1Gbps lan card, a 1Gbps Switch, and a 1Gbps NAS drive. So one would have thought that 1Gbps throughput should be achievable?

Well, copying 100Gb of data managed to sustain 10MB/s transfer rate which by my calcs is around 80Mbps? So not even that of a 100Mbps LAN! Achieving over 100MB/s would give me closer to gigabit LAN speeds no?

Or am I missing something really obvious? I understand that most network devices only ever "peak" at full bandwidth, but I'd have thought I'd be able to sustain a throughput of more than 10MB/s...

[Mark]

Or am I missing something really obvious?

Yes. :)

You need to factor in the speed of the hard disk(s), the performance os the OS (particularly on the NAS), any AntiVirus software, transmission overheads, and so forth.

Factor all that in and you're doing pretty well with 80Mbps. :)

[Will]

Up to 88Mbps now... ;)

Ok, the HDDs are pretty fast SATA 7200rpm drives they score 6.0 on windows 7

AV is AVG.

So it's just labour intensive overheads I guess then.... how frustrating.

[Del Lardo]

What NAS do you have? 99% sure it would be that, I'll explain after I've eaten.

[Mark]

I'll also go with NAS then (though the HDDs will max out way before 1Gbps). Many of them have design limitations inherent in the hardware. A few well-designed ones don't have this issue, but many do.

[Will]

http://www.wdc.com/en/products/Products.asp?DriveID=587

[Del Lardo]

http://www.wdc.com/en/products/Products.asp?DriveID=587

I shouldn't ;D but I couldn't have been any more correct. I used to have a WD MyBook NAS and it was the biggest POS ever. It would max out at 4.5MB/sec that's 36mbit despite having a gbit network interface. Basically that was all the chipset (HD to ethernet) could cope with.

On the same network with a Netgear NV+ NAS I would regularly see 600-700mbit when transferring between NASs and even copying files to my laptop over ethernet would achieve 300+mbit

[Will]

Fair enough - it's been a strong reliable drive though and works well. But I'm not a power user, so it suits my need.

Cool at least I know where the potential issue is. :)

[Mark]

Same as me. I have a Drobo which is even slower but I'm happy nonetheless as it serves it's purpose very well.

[Dymetrie]

Don't forget that ethernet is only 65% efficient (guess who's just finished an IP networking course :p), but you'll be stuffed if the HD to ethernet bus is pants...

Saying that, my mediabox gets attrocious transfer rates (1-2MBps on a 54mbps wireless connection) when transferring stuff over the network, but when it's downloading from iplayer it'll easily get 4-5MBps, which is weird. All I can think of is that it's the HD to ethernet on my main PC, but that works fine transferring to my netbook (or Mrs Dym's iBook) and I get excellent transfer speeds when copying files to USB.

Maybe I should buy a decent wireless network card for my mediabox, rather than the really **** one I did buy :D

[Will]

It's just a shame that fast computers with fast HDDs, and fast network cards don't perform to spec.

I miss my optical switches and raid arrays :( (I used to get sustained throughput of over 80MB/s)

[Burble]

Don't forget that ethernet is only 65% efficient (guess who's just finished an IP networking course :p)

They're over simplifying things massively with that statement.

You need to factor in cable length, connection speed (gigabit, 100Mbit etc...), MTU, what layer of the OSI model you're talking about, TCP? UDP? Routed? Switched? Transparent?

[Will]

It's only a layer 2, 1Gbps switch, nothing sophisticated. I'd hazard a guess that Windows 7 carries a lot of overheads. I disabled IPv6 (which seems to be on by default on W7) and it seems to have improved the throughput by a little - achieved 13MB/s \o/

[Dymetrie]

They're over simplifying things massively with that statement.

You need to factor in cable length, connection speed (gigabit, 100Mbit etc...), MTU, what layer of the OSI model you're talking about, TCP? UDP? Routed? Switched? Transparent?

Well it wasn't a CCNA....

Aiming to get that one next year :p