Re: [Qemu-devel] Some uncertain about implementing stream optimized writing

[Fam Zheng]

No error report with writing (dd of=/dev/sda ...), but can't change
data, (dd if=/dev/sda) dump unchanged.

On Wed, Jun 29, 2011 at 1:47 PM, Stefan Hajnoczi <address@hidden> wrote:
> On Wed, Jun 29, 2011 at 5:47 AM, Fam Zheng <address@hidden> wrote:
>> Stream optimized VMDK image allocates minimized space for a compressed
>> cluster, which means if there is high compress ratio, a cluster
>> possibly only takes one physical sector in the file. It makes
>> overwriting hard, especially when new data needs more sectors than
>> previously allocated.
>>
>> Attach the image to VMware and boot the VM to test this format, it
>> seems that VMware wouldn’t do write to allocated clusters, but can
>> allocate new cluster to save data.
>
> What happens when the VM writes to allocated clusters?  EIO?
>
> Stefan
>



-- 
Best regards!
Fam Zheng