Dynamic Disks and Recovery

Posted by kyle on December 10th, 2009 filed in Misc, Windows 7, Windows 7 Deployment

So – you might recall my post a little while ago about my boot to VHD issues – that I solved by making room on the drive.

So .. all was working well until as part of a demo I used the only machine that was available at the time and used that box to demo converting the disk drive to a dynamic disk – this then enabled me to do volume spanning etc..

So – fast forward to me the booting up into my VHD boot again – and then once more getting Blue Screens – mmm.. i thought I had solved that problem .. indeed.. I had – then I created another one!

So the issue was that for boot to VHD to work – it cannot be stored on a parent disk configured as a dynamic disk – this I did not know – and only found when I was hunting to see what the issue might have been.. http://technet.microsoft.com/en-us/library/dd799282(WS.10).aspx

So.. therefore I needed to convert from Dynamic to Basic – not an operation to be taken lightly as it traditionally involves taking the option to “Convert to Basic Disk” in Disk Management – and by convert it means – wipe everything and start again. So I was ready to do a complete rebuild – when a friend (Kim – you know who you are!) suggested to use the image backup in Windows 7  to do the full back up – destroy the disk and then start again – good thinking.. so I set about do this. For good measure I also used the backup facility on my Windows Home Server to create another copy… so far so good..

Then I began the process of doing a system restore – and then the troubles started

So .. what it seems (and further reading leans this way – but more testing is required and will be forthcoming – that doing image backups of a dynamic disk is not a good idea – I have found on various blogs (including the Windows Backup Team’s blog) that there is issues with backing up to a dynamic disk – basically you can do it but not restore from it – but I have also found that the image backup itself will not restore if it was from a dynamic disk in the first place. The backup completes – the files are certainly there – but the restore process does not work.

When I tried to use the system image restore option of the Windows 7 disk – I was given an error about not having the correct version of winpe (the 64bit version – which is what I was using) or the image was corrupt.

So – I went looking for other options – and found this. A handy hex editor that will edit the disk configuration. So there is a non-distructive way of changing from Dynamic to Basic disks (with a very large addendum as you will see!) Also read the whole thing before you start – you will see that there are some big gotcha’s..

The steps that I used were:

WARNING – THIS HAS THE ABILITY TO COMPLETELY DESTROY ALL ACCESS TO YOU YOUR DATA  – DO THIS AT YOUR OWN RISK – DO NOT BLAME ME IF IT GOES HORRIBLY WRONG – just saying is all .. this is all on you

1. Do a complete back up – I did 2 – the image backup and the WHS backup.

2. Download Hxd – I used the non-install version – and put it on a USB disk – you could equally download the install version – but I used the non-install version so I did not have to put anything on the HDD.

3. Run the exe. As this is on a Windows 7 machine I needed to run it as Administrator (yes – I run my own boxes with UAC turned on

4. I then selected my disk – using the menu –

then – in this case I knew the drive that I wanted to convert back – so I selected the disk 1 – disk 2 here is actually not a drive but a mounted VHD – more on that later. When you uncheck the Read-Only – which you need to do and then click on ok here you get a warning about the drive and what you are doing and how it could destroy your data – just in case my warning above was not enough.

5. Now you will see the contents of your drive – in hex form – do not change anything apart from what you need to – otherwise bad things will happen to your data (plague of frogs, etc)

Basically look in the Sector 0 1B0 – 1F0 area for the value 42 – logically you will have one for every volume you have – I had 3 – and then change the 42 to 07 – that is it – no changing any thing else.. at all .. then close and save changes.

6. I went then to Disk Management and found that disk 1 was now a basic disk – hooray – then I refreshed the view and got a Blue Screen of Death – ok – so this was not so cool.

7. Rebooted machine and Windows started fine – but then when I opened up Disk Management I found that my data drive had corrupted – mmm.. ok .. so why was that? Well – it was a spanned volume that had different parts of the drive – and that didn’t transfer across to the basic disk.

8. So that was fine as I had my backups right? yeeeeahhhh.. I went to the image restore option in Windows 7 and it could not find a valid image in the location that it was.. ok .. so I then head to Windows Home Server (remembering that I had backed up to both locations). Windows Home Server shows the backups – but I can’t restore the data drive – gets to 97% and then fails – mmm .. ok .. so Kyle is starting to get a little worried now – I noticed in WHS backup that the location for the backup for this machine is “missing” well.. that could be the problem – I wonder if that is due to the dynamic disk (a quick check of other backups restore fine and they have a location – but they are all for basic disks – so more testing to come on that)

9. So – I then looked in the location that I had put the system image backups – the vhd’s that were created were there – so the backup did work – it was just the restore process. No mind… I crack open Disk Management and then mount the VHD of the data drive and then manually copy the files to the newly recreated data partition on my laptop.

So – not the prettiest solution – but what the heck – it works – and it meant that I did not have to do a complete rebuild to convert from Dynamic to Basic.

I will be doing some more testing to see if any of the backup issues were actually from the Dynamic Disk or if it was just strange coincidence.. I am betting against strange coincidence.. but we shall see..

Anyway – enjoy!

Cheers

kyle