def _InstanceDiskSizeSum(self):
    inst_disks = self.cfg.GetInstanceDisks(self.instance.uuid)
    return sum([d.size for d in inst_disks])
Calculates the size of all the disks of the instance used in this LU.
dataset/ETHPy150Open ganeti/ganeti/lib/cmdlib/backup.py/LUBackupExport._InstanceDiskSizeSum