So this may not be the exact answer and will want double checking…
But basically SMVI (as does SMHV with Hyper-V) when they backup the virtual machine, they trigger a VSS call inside the VM… when VSS is triggered it ensures that all vss aware components in the VM are in a ready for backup state, so logs flushed, quisced and writes cached in memory and not committed to disk…
So in that way the contents of the VM are consistent…if the VM has exchange in it for instance, Exchange would be sat in hot standby ready to be backed up, so in the way would be consistent within the VM when its snapshotted…
I’m not quite sure of the difference between 2008 and 2003 as I would of assumed they all ran the same, so I would think this is a difference between how 2008 and 2003 handle those VSS calls rather than anything to do with SMVI.
Couple of caveats I’ve found with this…if you want proper consistency in the VM ensure you’re running snapdrive, then the machine is aware its installed on a NetApp based array… and also I’ve seen problems when you use the vmware tools VSS provider in the vm’s…this is a known issue with SnapDrive and VMware, so its probably wise to reconfigure vmtools to remove the vmware vss provider…and let the Microsoft one handle the work…
Last thing..is although the contents of the vm are consistent, this does not mean you have a recoverable backup point for your application, the whole VM still needs recovering really if you wanted to role back…so if you have Exchange in a VM…just because its consistent it doesn’t mean you can recover Exchange on its own, it has to be the whole VM… its not a replacement for using SME or SMSQL etc in the vm’s…
Hope that helps, its my take on it…and would be worth confirming if you can…
Regards
Paul.