I have three Server 2012R2 core edition hosts, running Hyper-V joined in a cluster. They share a number of CSV's. Tonight a customer called and needed an extension of a virtual disk of one of his VMs. Since there was not enough room left on the CSV, I first extended the LUN on our storage array from 1925GB to 2025GB.
Now I went into failover cluster manager, check what Hyper-V host is owner of the CSV. Then RDP-ed into that host, diskpart, rescan..... no change. I even rebooted the host, but I can't see the new LUN size on the Hyper-V host.