Do be able to move VMs between XenServers without shutting them down you need to create a pool

You could do this via GUI:

But I ran into problems since I have one ML115 G1 and one G5 with different CPUs. The GUI gave me the error “This server’s hardware is incompatible with the master’s“:

Run cat /proc/cpuinfo to get details and see if the CPUs differ and you can force them even though they differ. Just be careful when doing XenMotion.

Go to XEN2 and run:
xe pool-join master-address=<hostname-of-other-host> master-username=root master-password=<password>

Also this gave me an error:
The hosts in this pool are not homogeneous.
Reason: CPUs differ

Well, you can force it by adding force=true, but in a production environment you would probably try to figure out why you get an error since settings in BIOS (cpu flags) might be configured differently.

After a few seconds you should see the pool in XenCenter.

To add storage in StarWind, see part 1. When creating, make sure you select “Allow Multiple concurrent iSCSI connections (clustering)“, otherwise only one XenServer will be able to access it.

To add shared storage to the pool just add storage as we did in part 1 but instead of selecting the host when adding the storage, select the pool.