network card extremely slow host-to-guest file transfers in VMWare 2.0 beta 2

network card extremely slow host-to-guest file transfers in VMWare 2.0 beta 2
Published
by
kent
on June 20, 2008
in cyber security
. 2 Comments Tags: CentOS 4.0, CentOS 4.6, extremely slow network, guest, host, Intel 82566mm, large send offload, LSO, RHEL 4.0, RHEL4.6, slow file transfers, T61p, TCP segmentation offload, TSO, virtual machine, VMWare 2.0.

In case anyone else encounters this problem, I am making a quick post on this. I am running Windows Server 2008 Standard on my T61p Thinkpad with WVWare Server 2.0 beta 2 and have a guest OS running CentOS (RHEL) 4.6. NIC on my T61p is an Intel 82566MM GigE. With an SSH file transfer from my Win2k8 host to my CentOS 4 guest, encountered extreme slowness…like 5kb/s. That is like modem speed. I updated the CentOS kernel perhaps thinking that the problem would lie there. No change. A little googling and I found that TSO (tcp segmentation offload) needs to be turned off on the host OS NIC settings. The Windows equivalent of TSO on the Intel Driver is called Large Send Offload, or LSO. So I disabled this on the IPV4 properties and bingo. Now getting 800kb/s.