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I have 2 etch virtual machines. One's a clean Etch r9, the other is one of our server builds. On EtchR9 network speeds are 1Gbps. But on our server build we are only getting a max of 100Mbps, both network connections show they are connected at the same speed, same driver, same kernel.

I can test the speeds doing (ignore the ETA): On the clean etch: dd if=/dev/zero of=/tmp/zero.tmp bs=1M count=100; scp /tmp/zero.tmp fastserver:/tmp

Result I get is: zero.tmp 100% 100MB 25.0MB/s 00:04

Which is fine, the network is being used but it shows the from my ESXi machine to another server (which is 1Gb, and a physical machine) I'm getting faster than 10Mbps speeds.

But, from a server build we get: zero.tmp 100% 100MB 5.6MB/s 00:18

Both servers have the same kernel, same network driver loaded, same ESXi network settings. The physical links between the sender and the receiver are the same. I've tried rebuilding our server again and again but I keep getting these slow network speeds. The only solution I can think of atm is to try using the VMXNet3 Driver, but I haven't had any luck getting it to install.

While I don't expect a off-the-bat solution. Any tips on where I can check or look would be greatly appreciated!

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Not that it answers your question or anything, but have you considered upgrading? etch is end-of-life, and lenny may be ending soon, the faq only mentions there will be a year of support after the squeeze release. – Zoredache Dec 20 '11 at 22:07

Assuming you have vmware tools installed on both virtual servers (of course you do - best practice here) - I would say check your virtual hardware shell to see if both virtual network cards are set to the E1000 driver (assuming 64bit Linux here) or the flexible adapter if it's 32bit to ensure they both match. I'd also check the vSwitch to see if you're doing some kind of load balancing or throttling.

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A downloaded vmware appliance (Openfiler x64) was using the "flexible" network driver. That gave me just 100 Mbps of throughput even though the ESXi physical server had a 1Gbps network.

Changing to E1000 as the network driver in the appliance .vmx file resolved it and I now get ~500Mbps (my desktop computer can't handle faster file downloads).

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