[vbox-dev] stream optimized vmdk file layout??

Stuart Maclean stuart at apl.washington.edu
Tue Oct 28 16:37:43 GMT 2014


I know this is more one for the VMWare folks, but since (a) Virtual Box 
supports importing .ovf, which include a vmdk file in 'stream optimized 
format' and (b) I am already subscribed to this list, I thought it worth 
a try...

VMWare's specs on VMDK disk layout (e.g. 
https://www.vmware.com/support/developer/vddk/vmdk_50_technote.pdf) 
explain that for the stream-optimized  variant of vmdk disks, the first 
'compressed grain' follows the descriptor.

However, in .vmdk files produced by the 'packer' tool (http://packer.io) 
it appears that the first grain's data does not follow the descriptor, 
but rather sits in the sector of the file after the number of advertised 
'overhead' sectors (a field in the sparse extent header).

Any one shed any light on this?

Thanks

Stuart




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