Need to spec a new 2012 R2 server and thinking about putting the Hyper-V host partition on a pair of software mirrored SATA drives for resilience.

I also like the idea before doing any updates, as I have often done on server 2003, of shutting down the server and pulling out one of the mirrored system drives . If there is a problem the server can be booted from the original drive. If no problem the older drive can be hot-plugged back in and synchronized with the running drive.

Question is can this be done easily.

It seems to me there are two methods of mirroring a pair of drives in Windows 2012 R2:

  1. Storage pool / mirrored virtual disk
  2. Disk management mirrored physical disks

Option 1: Is it possible to boot from a storage pool array? Option 2: Assuming the server will have arrived with the Hyper-V host installed can I add another disk to this to create the mirror or will that wipe all data on the existing disk?

Or is there a better way of doing this.


You cannot boot from a Storage Spaces volume.

You can run Hyper-V 2012 (and R2) from a mirrored volume on dynamic disks (which can absolutely be SATA disks). For very low-end scenarios (like one of my test lab servers, for example) this works fine. Adding a mirrored volume with diskpart is a viable option and will not cause any data loss in the already-installed boot volume.

Whether this is appropriate redundancy for your application is up to you to decide. Windows isn't as likely to continue running in the face of a failed disk as a hardware RAID controller would be.

  • Option 2 it is then using diskpart to create the mirror if that is necessary over the usual Disk Management GUI. – NickC Jan 6 '14 at 21:16

Personally I always recommend hardware raid, preferably with a dedicated raid controller. You didn't mention the server's hardware specs so not sure what's viable there. With hardware raid it is (generally) pretty invisible to the OS what you are doing on the raid.

Don't forget, if "resilience" is your goal, that all disks in the host need raid, even temp drives, since a failure there causes a shutdown.

So I'd recommend (2) with hardware mirroring.

  • The hardware vs software RAID issue is getting interesting w/ Storage Spaces. It feels like Microsoft is taking an anti-hardware RAID stance. Personally, I've had success w/ Windows software RAID-1 in small installations for years (going back to NT 4). I've been scared of Microsoft's software striping (and parity) since getting burned in a test w/ some flaky SCSI disks back in the NT 4 days. I've always used hardware RAID whenever I needed RAID-5, RAID-10, etc. Having said that, I've also been burned by failed RAID controllers causing loss of access to hardware-managed RAID volumes, too. – Evan Anderson Jan 5 '14 at 23:02
  • I'd also like to point out that storage arrays by vendors like EMC run on Windows Storage Server under the hood. Of course, they have a lot of special sauce built in, but still... – MDMarra Jan 5 '14 at 23:11
  • Like everyone else I have previously always insisted on hardware RAID but lets remember that creates a single point of failure. With virtual machines I think it makes more sense to use windows software RAID. That way, in theory, all the storage could be moved to another (different) machine and still keep working. Would just need the Hyper-V host partition reinstalled. – NickC Jan 6 '14 at 21:19

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