Array Setup and Networking

Zero-Copy Cloning with Hyper-V

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Zero-Copy Cloning with Hyper-V

We are in the process of setting up our new Nimble CS300 array and will be using Hyper-V. The BPG for Hyper-V documentation references "Zero-Copy Cloning" and that it can be used for the OS Volumes as it "greatly reduces the amount of storage required for virtual machines by eliminating duplicate files common to multiple operating system images". However, in my searching I have not been able to find any further information on how to actually configure Zero-Copy Cloning at the OS level in a Hyper-V environment. Does anyone have any good documentation on how this is accomplished?

The part that is not making any sense is how the cloning works if I create a VM with a VHDX. Let's say I create the volume, build my master virtual machine placing the Virtual Harddisk (vhdx) file on this volume, install Windows Server 2012 R2 with all updates and then sysprep this master image. If I clone that volume, all I am getting is a clone of the VHDX file that resides on this volume. In this scenario, how is the Nimble eliminating duplicate files common to multiple operating system images?

Valued Contributor

Re: Zero-Copy Cloning with Hyper-V

Zero-Copy Cloning is using "Pointer" technology.

While you prepared the master image VM in source LUN; doing a Zero-Copy Clone will result having a new volume having exact contents of its parent volume (including the volume size).

And the next step is just map the Newly Copied LUN to HyperV server (modify the access control list if needed) and LUN will be show up after disk rescan.

The Zero-Copy LUN itself almost consume no block usage on array.


Please note that the Zero-Copy LUN are both readable & writable; if data is being read; the array will just reference to the source LUN for those piece of data block.

For any data written to that LUN; the array will start consuming block in the free pool of the array.

Therefore the array won't store 2 exact copies of OS image instead of just referring to the parent LUN; not "eliminating duplicate" and is "no duplicate".

Honored Contributor

Re: Zero-Copy Cloning with Hyper-V

It might also be worth looking into using Microsoft Hyper-V SCVMM with Nimble Storage - our rapid VM deployment and cloning techniques utilise both SmartCopy (aka Zero Copy Clones) and ODX Copy Offload.

Nick Dyer
twitter: @nick_dyer_