{
  "node-name": "test1",
  "read-only": false,
  "driver": "vdi",
  "file": "test2"
}
{
  "driver": "file",
  "filename": "/path/to/i.img",
  "node-name": "test2",
  "auto-read-only": true,
  "discard": "unmap"
}