[vbox-dev] writing to VHD/VDI is 50% slower of VMDK?

Frank Mehnert Frank.Mehnert at Sun.COM
Mon Oct 19 10:15:37 GMT 2009

On Tuesday 13 October 2009, Huihong Luo wrote:
> This seems to be always the case, writing a large amount of data to vdi/vhd
> is much much slower than writing to a vmdk disk. 
> I am using the the vboxddu.dll code, and clone physical disk to virtual
> disk. 
> for example, clone 250G takes about 2.50 hrs to  a vmdk file,  whereas it
> takes 4 hrs to a vdi file, under exact conditions, quite reproducible.
> There is only writes to disks, no reads. 

So this is a Windows host, correct? I can't imagine the reason for
such a slowdown as there are not many differences between the backends.
One differnece between .vmdk and .vdi is the block size. This needs
further investigation.

Kind regards,

Dr.-Ing. Frank Mehnert    Sun Microsystems, Inc.    www.sun.com
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