Re: Transfer rate on LAN?
Date: 07/24/05

Date: Sun, 24 Jul 2005 11:26:35 +1000

On 23 Jul 2005 18:42:10 CST, John Heim <> wrote:
> My setup: I have a linux box with 2 ethernet cards serving as DHCP and
> caching DNS server. Eth0 is a 10 mb card connected to my DSL modem. The
> other card is 100 mb card that is connected to a hub.
Sounds okay to me.
> Will linux talk
> different speeds to the different cards?
Yes it will, unless you're benchmarking via the modem :)

> Maybe the whole network is slow
> because of that one card?
No, but what sort of transfer test are you using?

# mount /home/public/
# time dd if=/dev/zero of=/home/public/zeroes bs=1M count=100
100+0 records in
100+0 records out

real 0m11.953s
user 0m0.001s
sys 0m0.329s
That's over 8MB/s from a AMD K7 2600+ --> pII/400 box with quality
NICs (onboard via-rhine to Intel pro/100 - e100) via NFS transport.

Following sequence shows 2 Linux boxen talking to/from winxp with SMB

root@sempro:~# mount /mnt/linux/
root@sempro:~# time dd if=/dev/zero of=/mnt/linux/zeroe3 bs=1M count=100
100+0 records in
100+0 records out

real 0m15.401s <<== 6.5MB/S
user 0m0.000s
sys 0m0.538s
root@sempro:~# time dd of=/dev/null if=/mnt/linux/zeroe2 bs=1M count=100
100+0 records in
100+0 records out

real 0m15.433s
user 0m0.001s
sys 0m0.534s

peetoo:~$ mount /mnt/linux/
peetoo:~$ time dd if=/dev/zero of=/mnt/linux/zeroe2 bs=1M count=100
100+0 records in
100+0 records out

real 0m18.163s <<== 5.5MB/s
user 0m0.004s
sys 0m2.585s
peetoo:~$ time dd of=/dev/null if=/mnt/linux/zeroe3 bs=1M count=100
100+0 records in
100+0 records out

real 0m18.018s
user 0m0.005s
sys 0m1.152s

> I figured that the DSL modem is way slower than
> the NIC anyway so it wouldn't matter.

You are right, it does not matter. Check NICs you are using, even a
p233/mmx firewall box from/to peetoo box does 3.5MB/s / 3.9MB/s over
NFS with pro/100 <-> pro/100, like yours, the firewall has an old
10Mbps NIC going to the modem.


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