I have an Windows Server 2012 environment with Hyper-V virtualization. My VMs were running very well but my machine was running low on disk space.
After buying an new HDD and installing it on my machine, I exported all my machines to the new HDD, imported again and started them all.
After that, I could notice that all VMs were running with a very bad performance... local tasks running very slow, bad network traffic, slow even copying files. Looking at performance monitors (task manager, nagios, etc), the VMs are not using all resources... they barely are using it.
So, I moved one of the VMs back to the original VHD and this VM worked great again.
I need to migrate this VM's to the new HDD, but I need to deal with this performance issue.
Do you have any tip to troubleshoot this problem?