Virtualbox 4.1.8 allows VMS clustering LAVC

Virtualbox 4.1.8 added the ability to indicate that the client will use an interface in promiscuous mode.

By setting this on the interfaces used by FreeAXP and SimH, I am able to create an LAVC on a Macbook laptop.

While it seemed to work well at first, I started getting issues where the cluster would loose connectivity.

It seemed to be related to the network interfaces on Windows that were dedicated to the emulator suddenly stop communicating with the outside world, and since the FreeAXP node was the voting node in the cluster, the entire cluster would hang. I would have to reboot the Windows 7 VM to get the network interface working again.

I just recently upgraded to VirtualBox 4.1.14 and so far it is working much better. It has only been a couple of days.

I have had two cases of FreeAXP on Virtualbox 4.1.14 loosing network connectivity.

This requires rebooting the Windows VM to fix.

It looks like I need to either downgrade to Virtual Box 3.1.8 or convert it to two standalone nodes.

The downgrade to Virtual Box 3.1.8 failed. Apparently I created my Windows 7 VM with a later version, so it can not downgrade.

A check shows a new version Virtual Box 4.1.16 is out, so installing it to see if it works any better.

After about 1 day of 4.1.16, one of the network adapters has stopped passing traffic.

Looks like either periodic reboots of the Windows VM or break the cluster into standalone nodes.

The cluster could rarely survive the laptop being suspended for transport anyway.

While other times I was not using the system at the time that the network adapter stopped functioning, this time I was doing a file copy over the adapter that quit.

Precisely, I have Cygwin installed on the Windows 7 host, and then have Cygwin NFS set up to serve files to VMS.

The VMS emulator has the disk mounted.

I was replicating a directory tree by just copying the directories from an unpacked curl tarball on the NFS volume to a local emulator volume. It got part way through and the session hung. Ping confirmed that the network adapter had shut down.

As I have changed quite a bit since the original cluster with Virtual Box 3.1.8, this issue may not be related to it being in a cluster.

I will also note that the Ubuntu VM running SimH has never seen any issues with Virtual Box 4.x.

I am using the Red-Hat Paravirtualized drivers for that interface to get the best performance.

I think that the next step is to change that adapter from the paravirtualized one to the default adapter type that Virtual box configures and see if that makes a difference when I reboot this evening.