Terrible network performance

[brettg]

Hi All

I've been trying to deploy a KVM host on CentOS and I've run into a bit of a show stopper with the network performance on the host.

Initially I built the server on CentOS 6 x64 but noticed that the network performance for scp transfers was unusably slow.

A 512Mb test tarball took 12min 30secs @ ~700KB/s to copy to the host.

I've spent a fair amount of time on google and come up with nothing.

To confirm that it is not a hardware or network issue, I booted the same server up using a Ubuntu LiveCD.

The same copy as before completed in 1 min , 43 secs @ 6.4MB/s

Thinking it might be a problem with the relatively new CentOS6, I reloaded the server wth CentOS 5.5.

This produced identical results to the original CentOS6 install.

Clearly there is a problem somewhere with CentOS on this server (IBM x3250).

Any guidance gratefully accepted.

Here is the output of ethtool;

Settings for eth0:
Supported ports: [ TP ]
Supported link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Full
Supports auto-negotiation: Yes
Advertised link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Full
Advertised auto-negotiation: Yes
Speed: 100Mb/s
Duplex: Full
Port: Twisted Pair
PHYAD: 1
Transceiver: internal
Auto-negotiation: on
Supports Wake-on: g
Wake-on: g
Link detected: yes

lspci

04:00.0 Ethernet controller: Broadcom Corporation NetXtreme II BCM5708 Gigabit Ethernet (rev 12)

[pschaff]

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