Xen VM host hard drive access

I've now got my unRAID based Xen system fairly stable but getting my VMs to directly access physical hard drives has been a bit of a learning curve.

I have a Windows 7 VM that runs Mediaportal / ArgusTV server installs with my Octopus tuner cards passed through. This VM is my 'tvserver' and manages all TV scheduling, tuning and streaming.

I also have a Windows 8.1 client that runs MediaPortal and Netflix with GPU and USB passthrough. This drives my lounge TV via HDMI out from an AMD HD5xxx video card.

My biggest issue though has been arranging storage on the Win 7 tvserver for both timeshifing and recording storage.

Both VMs currently boot from .img files stored on my unRAID shares. I could set up another .img file there but don't want to as I'm sure I'll hit performance issues as the unRAID share is parity protected and thus has poor enough write speeds. 9I don't have a cache drive yet as I'm still in test build mode on a basic unRAID licence.

Xen USB Passthrough

I've been having some trouble passing through USB controllers to Windows VMs running on my unRAID 6.0beta3 Xen host.

Specifically, passing through the full USB controller using PCI Passthrough, I was seeing errors similar to the following when creating or destroying VMs;

libxl: error: libxl_pci.c:1001:libxl__device_pci_reset: The kernel doesn't support reset from sysfs for PCI device 0000:00:12.2 

USB access in the VM would be hit or miss and I'd often get an error on Dom0 indicating that IRQ #18 had been disabled.

A little case surgery

I'm beginning to run out of expansion card space in my system case with multiple graphics cards, tv tuners and hard drive controllers already installed and possibly more to come.

While my motherboard has 6x PCIe slots and a PCI, it's starting to get tight in there.

I've gone for the Octopus system from Digital Devices for TV & Satellite tuning. This  allows me attach up to 4x dual tuners to a single PCIe x1 card. It's possible to fit two cards per full-height bracket but even at that, I'm occupying a valuable space with a card that doesn't need to plug in to a slot.

unRAID 6.0 Xen Guest GPU Passthrough

It's been a blast following the progress over at unRAID forums as the build up to and release of 64 bit version 6.0 took place. I personally learned a lot virtualizing unRAID in KVM on ManjaroBox but the latest unRAID beta (v 6.0b3) is now out and allows for hosting of virtual machines in unRAID itself thanks to the enabling of Xen.

A big part of my requirement is to establish two or more virtual HTPCs. For this to work, it's necessary to 'pass through' physical graphics cards to the virtual machines.

Here's how to do it;