VMWare network issue with XPSP3 and host shares

Back in September last year when I set up my VM work environment, I’d started using Win2K as the host OS, with the hope of saving as much memory as possible for the guests. As I wrote here, there were a few issues, including one of dropped network connections when doing high bandwidth transfers between the guest and a share mapped from the host.

The problem disappeared when I switched to XP as the host OS but XP SP3 seems to have reintroduced it. Here are the circumstances which causes it:

The host has a network interface with gigabit capabilities but its only connected to a 100mbit hub. You use bridged networking for your guests and map a drive from the host on the guest. You then copy large files to that share. The connection will drop out. I’ve reproduced it on 2 PCs here with XPSP3, with VMWare version 6.01 and 6.03.

What is happening is the guest-to-host transfer is occuring at speeds greater than the physical interface can occur, which is possible since the data doesnt have to actually go out on the physical device. This is now causing the network stack to freak out and drop the connection. It was OK pre SP3.

As I briefly mentioned in my previous post there are several solutions.

I added a second network interface to the guest and set it up to be host only. I then configured vmnet1 on the host to use and the corresponding interface on the guest to (it helps renaming the guest’s network interfaces once you determine which is mapped to which physical interface). In the guest I then created an entry in /windows/system32/drivers/etc/hosts to map my host’s name to the address of the host on the host-only network. Using the host’s name in the guest for shares etc now will be guaranteed to go via the correct virtual interface.

After doing this I used the host Task Manager’s Network window to check the transfer speed for file writes to the host’s share from the guest, this showed about 200mbit/second on the vmnet1 (host only) interface.

I guess given crash issues others are having with XPSP3 (AMD related it seems) I should consider myself lucky if this is the worst issue I have with it.