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Re: [Xen-users] Network performance in virtual machine (good upload spee

To: Martin Nilsson <martin@xxxxxx>
Subject: Re: [Xen-users] Network performance in virtual machine (good upload speed, bad download)
From: Fraser Campbell <fraser@xxxxxxxxxxxxxxxxxxxxx>
Date: Mon, 28 Nov 2005 11:57:18 -0500
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Martin Nilsson wrote:

performance in the virtual machine. When I upload data, I get good speeds, around 6-7 MB/s which I think is ok on a 100 Mbit network. When I download however, I only get ~300 KB/s. On the host machine I get good speed in both direction.

Check that your NIC is set for full duplex, I have seen symptoms like you mention (outside of Xen) whenever the NIC is half-duplex.

As a rule we always use the following command on 100Mb interfaces:

  ethtool -s ethX autoneg off duplex full speed 100

Good luck,

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