December, 2013 | gimpland.org

Citrix XenServer 6.1 Internal error: File “xapi_xenops.ml”, line 1788, characters 3-9: Assertion failed

Today I rebooted a xen host, everything came back up as I would expect, and after trying to live migrate VMs back onto the host I got this error message.

Internal error: File "xapi_xenops.ml", line 1788, characters 3-9: Assertion failed

I thought it was something wrong with xencenter, but then tried via command line and got this error:

Error code: SR_BACKEND_FAILURE_46
Error parameters: , The VDI is not available [opterr=VDI SOME-UUID already attached RW]

The message “The VDI is not available” I’ve seen many times before and I knew what to do.

Citrix XenServer PCI Passthrough

Sometimes you need to use a PCI device on a virtual machine. We have a vendor who has supplied a USB dongle for software licensing, which is really annoying. Their software doesn’t merit it’s own server, so we want to put it into our Xenserver pool.

Shutdown the VM you want to attach your device too.
SSH into the host that has your PCI device. Use the following command to locate the PCI ID for your device. Should look something like this “00:1d.7″
```
lspci -v
```
Now locate the UUID for the VM you want to attach the PCI device to with the following command
```
xe vm-list
```

Now use the following command to set the pass through

xe vm-param-set other-config:pci=0/"PCI ID" uuid="UUID of VM"

Now boot the VM and check if your device is now attached. If not, make sure you are using the correct PCI ID. USB devices can get tricky, as there maybe many USB devices listed.