A friend of my was running his Hyper-V 2012R2 environment with differencing disks. Not so good for performance, so he asked if he could migrate them to normal disks.
Luckily I had played a bit with differencing disks in my lab environment to see how it works. So I could use this lab to test the migration path.
This is the parent disk which I used for all lab machines.
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As you can see, the LB-DC01 is using this disk as it’s parent disk.
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The LB-DC01 has a checkpoint. All checkpoints needs to be removed first.
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When the checkpoint had been removed, its merged into it’s original disk. Notice the increased disk size.
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Just to be sure, I export the machine to a save place as a backup.
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When the export operation has finished, it created a complete copy of the vm, including a copy of the parent disk.
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Now it’s time to merge the disk. At this point the vm needs to be turned off. Edit the disk and select the Merge option.
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In the Configure Disk window, select To a new virtual hard disk and choose the appropriate hard disk type.
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After the operations has finished, the new disk has been created.
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The last step is to configure the vm and point the hard drive to the newly created vhdx file.
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After starting the vm, everything works fine!
