I am have a problem with an Ubuntu install (10.04) and a Intel gigabit Ethernet card both the e1000e built into the motherboard and the e1000 in the pci slot.

When I scp a file from my Mac server to my Mac laptop I get about 40MB/sec transfer. I am ok with this. If I scp the same file from my Mac server to my Ubuntu server it starts with 58MB/sec and starts decreasing from there until it finally transfers 7MB/sec.

This happens with Ubuntu 10.04, 10.10 and 11.04. So I tried Fedora Core 14 Live CD and did the same scp. Low and behold 48MB/sec, perfect!

Whats up with my Ubuntu install? What should I be looking at. The problem occurs with the built in e1000e as well and the brand spanking new e1000 that was delivered yesterday.

I am not a networking guru by any means but have used Linux for the last 15 yrs and I am not sure how to solve this.

Right now I am waiting for Fedora Core 15 to get released and tempted to wipe my Ubuntu install just to get decent network performance.

Thanks
Peter

you can start by checking with ethtool:
do the equivalent on your macs and compare. Look especially at the duplex and speed values.

Also, you can test the write speed of your disk on the linux machine by creating a 1GB file:

Thee dd command revealed the problem. I have a 3ware raid card without a battery backup unit (BBU). Because of this the write cache is not enabled. I turned on the write cache even though I didn't have a BBU (do now) and through put is now what I would consider normal. Thanks for the help.