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After some struggle, I finally managed to set up Hyper-V 2008 R2 on our server. So I connected to it using the Hyper-V Manager from a Windows 7 client and used the "New Virtual Machine Wizard". I set up a 350GB virtual hard disk.

So I hit the "finish" button and the Hyper-V manager has been working for > 24hours now, showing merely a dialog "Creating Disk". A console on the Hyper-V still reports 99.9% free space on the HD, but the machines HD LED flashes from time to time (making a rather idle impression, it's not flashing frenetically).

Does this usually take this long? Is there a way to find out whether it's still working or just idling? Should I repeat the process? Guides on the net tell me to be patient, but >1d seems a bit extreme!?

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It shouldn't take more than about 1 hour per 0.5 GB; I'd kill the Hyper-V MMC, then try opening it again and creating the HD. – Chris S May 8 '10 at 19:58
1 hour / 0.5 gb = 700 hours for 350gb ;) – TomTom May 9 '10 at 1:31
You gotta be kidding?! That is one month! That can't be, I mean that really makes the VM completely useless... – mnemosyn May 9 '10 at 11:32
Not kidding. Just making some maths. I seriously doubt 1 hour per 0.5gb to start with;) – TomTom May 10 '10 at 10:57
1 hour per 0.5gb is crazy talk. On my dev system (1 local 7200rpm drive) it can do a 5.0gb fixed drive in about 2.5 minutes. A "5.0gb" dynamic disk takes about 10 seconds. Definitely something wrong if it is taking more than 24 hours to create a disk. – MattB May 10 '10 at 14:09

s the storage directly attached to the server? I had cases where I had storage to create fixed size vhd's on either a NAS or a SAN, and in particular on NAS (which had a non-windows native OS) it took very looooong as well. I always waited, and usually the process always finished succesfully.

Good luck!

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The disks are simple SATA II disks in a RAID 1 array. I see it takes a long time, but Chris suggested a shocking 1 hour per 0.5GB. That translates into a month (!) for 350GB... – mnemosyn May 9 '10 at 11:34
up vote 1 down vote accepted

The "New Virtual Machine Wizard" sets up dynamically expanding disks by default. Setting up a dynamically expanding disk takes no more than a second, which is what I found after aborting the process and rebooting both client and server.

I haven't tried setting up a fixed disk, but I doubt it takes 1h for 0.5GB - that'd make it totally worthless because setup times would be in the range of several months. Did you mean 0.5TB, Chris S?

It seems the Hyper-V manager that ran for days was simply hanging. In general, the Hyper-V Manager is an extremely unstable piece of software, often leaving (modal) dialogs open that cannot be closed by any means other than killing mmc.exe.

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I've not had the same issues with the Hyper V manager and we use Hyper V extensively here. Make sure that you're running the latest version of the tools. – Tatas Jul 1 '11 at 16:08

I used VhdTool to quickly create a virtual disk of the correct size and then just used Hyper-V to create the machine and reference the blank VHD file. From there you can insert your OS installation media and start the machine. This was a lot faster than the seemingly never ending "Creating disk..." method that Hyper-V offers.

You can download the tool and get instructions here:

e.g. at the cmd prompt: VhdTool.exe /create "Clean10Gb.vhd" 10737418240

They do say only to do it with servers you trust because there is a security implication in not zeroing out all the underlying data on the hard drive.

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do you know if there is an equivalent tool for the new vhdx format yet? – BlackICE Sep 26 '12 at 16:56

Ok, I see this issue if you try it from non-domain HyperV host --> Creating VM on Domain HyperV host (with using the storage on domain host). Once I tried same steps going from 1 host and using it's own storage creation took seconds. Possible solution: use hyperv manager of that host, where you want to place the VM on.

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