def METHOD_NAME(self):
    # Mirror speed limit doesn't work well enough, it seems that mirror
    # will run many parallel requests anyway. MAX_IN_FLIGHT is 16 and
    # MAX_IO_BYTES is 1M in mirror.c, so let's use 20M disk.
    self.init_vm(20 * 1024 * 1024)
    self.start_job('blockdev-mirror')
    self.cancel_job()