How to migrate Proxmox VM to another computer in a cluster

Original:

I am running Proxmox 4.2 with a Debian 8 (Jessie) VM. I have DRBD running between two desktop computers in a cluster and I have a third node in the cluster which is a laptop not running DRBD. It is going to be used for offline migration (I'll discuss that later).

Problem #1

In the Proxmox web GUI, I live migrate the VM from one computer to the other, but it goes offline sometimes after it migrates. I was running a continuous ping during the migration, and once the migration finished, the pings wouldn't go through yesterday. If I powered down and restarted the VM the pings would go through.

I tried today however and the live migration worked and the server never went down. Are there any configuration settings that could be causing this? I'm happy it worked, but I can't implement this system if it has bugs.

Problem #2

The two desktop computers involved in the live migration are identical. The laptop has different RAM and disk space, but it is running Proxmox 4.2. I offline migrated the VM from desktop to desktop by moving the *.conf file in/etc/pve/nodes//qemu-server/ from the desktop to the desktop and running the qm start 100 (100 being my VM name), and it worked fine. But when I tried to do the same thing from desktop to laptop it didn't work and generated the following error:

org.freedesktop.DBus.Error.ServiceUnknown: The name
org.drbd.drbdmanaged was not provided by any .service files

If I go to the Proxmox web GUI and try to start the VM (which now appears under the laptop node), nothing happens.

How can I fix this? In order to offline migrate, do the specifications need to be the same? I don't have DRBD installed on the laptop either, which I don't think I would need it since I'm only using it for offline migration, but based on the error above it seems like I might.

UPDATE:

I installed drbdmanage (just like on the other two nodes and the error went away while performing offline migration. This new error occurred however:

drbd error: Object not found

UPDATE 2:

After getting the error:

drbd error: Object not found

I tested something out. Initially I had two network cables connected between the two desktops. One of them connected the two desktops and acted as the DRBD cable, and the others connected each to the internet. When offline migrating the VM from desktop to desktop, I had to power off the machine with the VM and then migrate.

I realized now that the reason the laptop offline migration was failing was because it didn't have a cable connecting itself to each of the other computers in the cluster directly. I realized this because I unplugged the DRBD cable between the two desktops and the same error occurred:

drbd error: Object not found

I don't have an extra Ethernet port on the laptop, but based on the test with the two desktops Problem #2 is solved.