I have been helping people around the world recover data from Hyper-V avhd chain disasters since 2009. I have helped people in a lot of countries and cities , some of which include.

I recently installed a 2 node Hyper-V cluster soon to be a 3 node and all was working really well until I added a DPM 2010 Agent.When I was trying to do a live migration it would move 100% but fail to start. So if I shutdown the vm and move to another host and try and start it. It still wont start!!!!! 😦

It was also affecting SCVMM , I could not push templates to my cluster.

I was starting to panic at this stage and was thinking I needed to rebuild my cluster, but the fix was really simple and required a few steps.

1) Start Registry Editor.
2) Visit the following registry key: “HKLM\SYSTEM\CurrentControlSet\Services\FsDepends”
3) Under the “FsDepends” key, change REG_DWORD value “Start” from “3” to “0”
4) Restart the computer

Another culprit was SOPHOS, I excluded cluster.exe , c:\clusterstorage and it still would fail. So I also excluded the volumes C:\Clusterstorage\volume1 , C:\Clusterstorage\volume2 etc.. and it all worked fine.

Also to remove any ISO images attached to any VM , Like exchange 2010SP1 iso, after the iso has been removed , go into cluster manager , right click on the virtual machine, click on more actions and refresh virtual machine configuration.

My live migration is working perfectly again.

I first posted about broken vhd – avhd chains in December 2009, And since then I have helped many people throughout the world in recovering their data and made some friends along the way.

I have recovered data for people in france, germany , uk, australia, usa, brazil

A guy called Dave Loughner from Innovative Solutions in New York pointed out a great utility for recovering data from avhd & vhds.

It is Disk Digger and only cost $14.99, Best money you will ever spend if your really stuck. Dave tried about 30 recovery products before coming across Disk Digger.

As of writing this http://www.diskdigger.org is down but you can download it here

Also a point to note. The disk digger solution is absolutely the last resort as nothing is as good as merging all avhds and having a healthy server at the end.Using disk digger will get you back up to 50% of your data but not all.

I ran into a situation where I needed to recover a lot of mailboxes via backup exec on an Exchange 2003 Server and needed to do it via a recovery storage group and exmerge.

But the problem was I did not have enough storage on the exchange server to recover with a RSG.And adding additional storage was not an option , next step for customer was a hardware upgrade for exch 2010.So luckily enough I had a Hyper-V Server with loads of storage so I did the following.

1. Created a new vm with a 500gb dynamic disk , added in a legacy adapter , 4gb ram , 4 virtual cpus.
2. Then started up the new vm and booted into the free nas os, selected the legacy adapter , set the legacy adapter to receive dhcp, took note of ip address.
3. Then logged into the free nas via the http://ip received from dhcp. User name: admin password:freenas
4.Configured freenas as per this article from Dave Lawlor
5. Then downloaded and installed latest microsoft iscsi initiator for Server 2003.
6. Connected to my freenas via iscsi and formatted my new volume.
7. Then moved my RSG to the new volume I created.

This was an interesting resolution to my problem as I couldnt locate the RSG on anything but a local drive and exchange thought my new volume was a local drive.

Now this problem was probably a once off but it is a really simple way for people to play around with iscsi and san technology and its free.