Re: [Question] qemu-img convert block alignment

[Zhenyu Ye]

ping?

On 2021/4/2 11:52, Zhenyu Ye wrote:
> Hi all,
> 
> commit 8dcd3c9b91 ("qemu-img: align result of is_allocated_sectors")
> introduces block alignment when doing qemu-img convert. However, the
> alignment is:
> 
>       s.alignment = MAX(pow2floor(s.min_sparse),
>                       DIV_ROUND_UP(out_bs->bl.request_alignment,
>                                    BDRV_SECTOR_SIZE));
> 
> (where the default s.min_sparse is 8)
> When the target device's bl.request_alignment is smaller than 4K, this
> will cause additional write-zero overhead and makes the size of target
> file larger.
> 
> Is this as expected?  Should we change the MAX() to MIN()?
> 
> 
> Thanks,
> zhenyu
>