Migrate a Xen VDI to another storage repository (on the command line)

I had a virtual disk (VDI) attached to one of my VMs which wasn’t full (according to df on the VM) but was causing IO errors for all applications running in the VM.

Running xe vm-disk-list vm=$VM (where in VM is either the UUID or the name of the VM the disk is attached to) shows both the disks as well as the (names of) the storage repositories these disks are stored in. This information is available under sr-name-label.

xe sr-list gives a complete list of storage repositories, from which I could find the UUID of the storage repository in question. Running xe sr-param-list uuid=$SRUUID shows how full the storage repository is:

      virtual-allocation ( RO): 4340072841216
    physical-utilisation ( RO): 1320537186304
           physical-size ( RO): 1320538832896

This one is almost completely full. But I had another storage repository available that wasn’t full. Thus I moved the VDI from one storage repository to the other:

xe vdi-pool-migrate uuid=$VDI sr-uuid=$NEWSRUUID
# prints NEWVDI uuid

After some time (depending on the size of the VDI that’s moved) this command returns and prints a new UUID which is the UUID of the moved VDI.

Note: Above command only works when the VM is running, which seemed a bit weird to me, but well …

Using xe vm-disk-list I then checked that the VM has been updated to use that new VDI, which it thankfully had.

I’m posting this because I had a really hard time finding some documentation about how to do this without XenCenter.