I have a couple of DC's running Server 2012 as Hyper-V guest machines. I have write caching disabled on the hosts RAID controller (no cache battery), but for some reason, I can't disable write caching on the VHDX virtual drives that the DC guest servers reside on. This has caused me issues twice during extended overnight power outages that have caused unclean shutdowns of the physical server, corrupting AD databases on the guest servers. I just spent four hours force-removing AD from one of the servers, rejoining, and fixing all the other associated issues due to corrupted AD databases.
How the heck do you disable write caching on the boot drive on a Hyper-V guest when the guest OS says the device does not allow the setting to be changed? Oh, the VHDX is mounted as an ATA device. Do I need to create a tiny VHDX to mount as an ATA device as a boot volume, and then install the OS on a SCSI mounted VHDX, or how else can I fix this problem?
Any suggestions would be greatly appreciated!