Re: [Qemu-devel] [PATCH v2 1/2] iotest 033: add misaligned write-zeroes test via truncate

[Alberto Garcia]

On Mon 12 Feb 2018 02:14:00 PM CET, Anton Nefedov wrote:
> +# Trigger truncate that would shrink qcow2 L1 table, which is done by
> +#   clearing one entry (8 bytes) with bdrv_co_pwrite_zeroes()
> +
> +echo
> +echo "=== Test misaligned write zeroes via truncate ==="
> +echo
> +
> +CLUSTER_SIZE=$((64 * 1024))
> +L2_COVERAGE=$(($CLUSTER_SIZE * $CLUSTER_SIZE / 8))
> +_make_test_img $(($L2_COVERAGE * 2))

If my numbers are correct, that's a 1GB image. For qcow2 this is not a
problem but I wonder if it's ok to create such large images for other
formats (for raw they should be sparse by default, but still).

Berto