I ran in circles for three days before I found a solution to this. It seems to be a unique problem that, lucky me, I created myself.
When I resized /dev/mapper/pve-root onto a second local drive and restarted the server, GRUB would throw and error that it couldn't "find...
Two node cluster, (A) Proxmox 5.0 and (B) Proxmox 5.1
One shared iSCSI with LVM
VM disks on iSCSI
I get the error in the subject line when trying to migrate an online VM or start a migrated VM.
What I've discovered is on node A, iSCSI is sdc and its LVM is sdd, while on node B it is just the...