iSCSI copy cause Windows 2012 OS to hang / crash / burn

[Dieselboy]

I too am confused. So your KVM hosts are intercepting  the iSCSI call from the VM and mounting the LUN at the hypervisor level even though you mounted it from the VM, not the hypervisor?!?!!?
And for some reason it doesn't do this for Win7 guests, just Win Server 2012?

Exactly correct. This is the default behaviour and the only way to "fix" is to edit config files and plan a custom Logical Volume filter, which "filters out" everything except your "storage domain(s)". It's complicated and there's no mention that this is required in the documentation. If I rebuild a Host, this filter needs to be put back so my Host config guide is getting a bit big

[wintermute000]

So basically, out of the box KVM, don't try to mount any iSCSI LUNs directly from VMs?

This is kind of stupid. Why intercept the call? If the VM is going to mount something that the Hypervisor presents, you have to do it manually (present it via the hyeporvisor storage stack) anyway, so why intercept anyhting at all, super confused.

[deanwebb]

So basically, out of the box KVM, don't try to mount any iSCSI LUNs directly from VMs?

This is kind of stupid. Why intercept the call? If the VM is going to mount something that the Hypervisor presents, you have to do it manually (present it via the hyeporvisor storage stack) anyway, so why intercept anyhting at all, super confused.

I agree. Dieselboy makes sense, the VM programming does not.

[Dieselboy]

so why intercept anyhting at all, super confused.

That was my argument. But when you start digging it seems that this is not commonly done by customers, well that's the feeling but it's hard to believe. An example of this is when I recently installed a Red Hat Virtualisation environment, I used the "self-hosted engine" which is the management server running on the Hypervisor within the system. During this deployment the script asks you what kind of storage you would like and I specified iSCSI (for a single LUN used by the management server). Later on once the deployment was complete and I logged into the management gui, the iSCSI LUN was configured as a storage domain which is strange considering you can only use it for the management VM.

It seems 1 LUN per virtual disk, ie direct LUN disk isn't commonly done. It's kind of expected that you're using storage domains, which apparently requires the Hypervisors to mount the volume on it'self. There should be documentation on this and how to configure the system for LUN disks. :/