I have:

Windows Server 2012 with Hyper-V and 2 VMs

x6 hard drives 500 GB capacity in software-RAID array (Window's Storage Spaces) for VM storage, x1 SSD boot drive for server host OS (and VM page files).

The array is in a RAID-10-like configuration, but with 2 stripes and 3 mirrors. (meaning, we lose 4 of the 6 drives to redundancy for a total of 1 TB array space)

We now have 2 external backup drives running on the server every night.

Currently, our VM storage arrary has 122 GB free of 927 GB capacity (805 GB used), but our data is not growing that fast.

Still, I want to reconfigure the array to be 3 stripes with 2 mirrors each because:

  • Database/Server Speed increase (I suspect 3 mirrors is slowing down writes, possibly waiting until all of the 3 drives have finished a write?)
  • Future storage space (3 stripes with 2 mirrors each would mean 1.5 TB total array space)
  • Cost efficiency (4 of 6 drives lost to redundancy currently vs. 3 of 6)

Because data is already on the disks, all that needs to happen is 2 drives (1 mirror from each stripe) need to get wiped, and the other 2 stripes need to split their data to the new 3rd stripe. I suspect this isn't possible tho.

Likely I'll have to erase all the data, destroy the array, use the 6 free drives to build a new array, and restore the data from a backup to the new array.

Is this safe? Will Window's backup restore old data to a new array or fuss? Does this seem the right way to go about this?

EDIT: I'm using Window Server 2012 and the Windows Backup utility that comes with it. The "software-RAID" in question is Windows Storage Spaces (all native tools to Server 2012).

  • If you downvote please leave me feedback how the question could be improved! It only needs a simple answer that anyone with more world-experience with Window's Storage Spaces and Backup would be able to answer – IT Bear Nov 7 '14 at 22:07

Windows Server Backup will handle backup and restore of the data you're talking about just fine. You can also just xcopy or robocopy the data, so long as the VMs are powered-down when you're making the copy.

I'd make two independent copies and verify them with cryptographic hashes before proceeding.

| improve this answer | |
  • I was digging into "WindowsImageBackup" looking for recognizable files or folders to do a hash-comparison on, until I realized what you meant. We have another PC here at work with a 1 TB drive we use for storing Machine Images; I was asked to back it up. It was actually easier for me to write a script (in Batch no less) that auto-mounts a VHD located on the backup disk, robocopy all changes from the data disk to the VHD, auto-unmount and show the log. A regular "Windows Backup" runs on the 80 GB C:, but my solution has been highly reliable so far. Is this a commonly used SysAdmin "fix"? – IT Bear Nov 14 '14 at 21:57
  • You do what you have to. >smile< I use a variety of different dodgy hacks to copy files, depending on requirements. – Evan Anderson Nov 14 '14 at 22:10

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