Win7 Boot from VHD (point!?)

dales

Hi all,

I've started studying for 70-680 and have been looking at booting from VHD but I am struggling at the moment to see the point of it.
Booting from VHD recognises all your machines own hardware (killing portability/migrations), theres a natural performance hit (not much but there is).

The only point of booting from a VHD is that you dont have to partition a disk, but to me it just seems like virtualization without any of the benefits (or its there just for the sake of it).

Am I missing something that makes it actually worth doing?

jibbajabba

Virtualization might not be possible everywhere. Maybe the hardware doesn't support etc., but booting from VHD still gives you the option to test several installs on the same piece of hardware without using multiple disks / partitions.

I'd say booting from VHD really is only good for test or development environments.

Plus when using virtualization you still run the OS on virtual hardware and again, booting from VHD means you can run several different applications and use the actual physical hardware and test compatibility etc. You could easily create multiple VHDs with different operating systems and boot from it .. Yes you can multiboot etc., but it might be more hassle especially if you want to test several different OS' on this PC / Server etc.

MentholMoose

Some benefits are listed here:
Understanding Virtual Hard Disks with Native Boot

I don't use this feature but it seems potentially useful for dev or testing environments. Imagine scenarios where you would want to use a VM, but you need access to the actual hardware.

For example, if you are doing some testing and need to rollback to a specific point in time over and over, with a regular physical machine you would take an image, then reapply that image for every rollback. With a VHD you can use a differencing disk, making a rollback much easier. Also dual/multi-boot is simplified.

tiersten

Booting from a VHD is only in the Windows 7 Enterprise and Ultimate editions. It is for testing and development and not for general use. W2K8 Server R2 also supports this.

MentholMoose's link has a list of uses for it.

dales

hmm yes I suppose so, I was aware that its only on ent/ult editions (gotta love technet direct subs), but I was thinking more along the lines that it could be used for unified imaging, if boot from vhd did actually give you proper emulated hardware then you could roll out one image to any pc regardless of make/model etc.

I think I was just imagining something abit more grand that it actually is plus the fact that it only supports 7 and 2k8 booting. Apart from the differencing I dont really see any benefit at the moment other than dev work.

Hyper-Me

If its only for testing why does WDS 2008 R2 support the deployment of VHD files in addition to WIMs?

MentholMoose

Hyper-Me wrote: »

If its only for testing why does WDS 2008 R2 support the deployment of VHD files in addition to WIMs?

To me the benefits are particularly clear for a dev environment (as in software/driver development, QA, etc.). I didn't mean non-production use only. Native boot VHD can certainly be used in production as long as you mind the various limitations.

The deployment tools all support VHD now as well as WIM, as you mention, so I think you can totally ditch WIM in favor of VHD and have a single standardized image format across your physical and virtual environments.

dales

Thanks for the info I'm still a little cloudy on one thing though, the MS press books seems to say that the VHD will recognise all your own hardware so for example it would recognise all the standard hardware for an HP desktop unit (no virtualized hardware) so the VHD could not be standardly rolled out to other makes and models.

I guess I need to test this out (have not had the chance yet) to get it clear in my head how this would actually work.

Hyper-Me

dales wrote: »

Thanks for the info I'm still a little cloudy on one thing though, the MS press books seems to say that the VHD will recognise all your own hardware so for example it would recognise all the standard hardware for an HP desktop unit (no virtualized hardware) so the VHD could not be standardly rolled out to other makes and models.

I guess I need to test this out (have not had the chance yet) to get it clear in my head how this would actually work.

Yes and No.

Native boot VHD does recognize and use the physical hardware, but the vhd could be sysprepped and other model drivers injected into it for use on other physical hardware as well. Just like a WIM image.

Hyper-Me

I think there are valid reasons to use this in a production non-developer situation.

Once you partition a drive you are mostly stuck if you've filled up the partitions to a certain extent. Data can get messed up/lost while manipulating partitions and it can be a headache.

You can set a native VHD boot for the system and allow other data storage on the rest of the drive, and make the VHD dynamic so it simply expands as needed if it fills up without the need to rework partitions and such.