How to reduce virtual machine disk size (Hyper-V)

I've found that the disk is usually the biggest bottleneck for our virtual machines. Especially if you're doing continuous integration across multiple VMs, you'll be doing a lot of reading and writing. If all the CI processes start at the same time, the problem is compounded.

The quickest way to get better performance may be to add physical drives and distribute your VMs across those drives.

Another way to get better performance would be a large RAID5 array. We've seen amazing performance in large VM clusters when you have lots of drives to spread the data across.

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.