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Introducing Hyper-V Quick Migration

In the Hyper-V world, lots of us talk about Live Migration. That is where a virtual machine (VM) is moved from one host to another with no perceived downtime. The caveat is that both hosts need be configured to use the same shared storage (such as a SAN or external drive array).

What if you want to move a virtual machine to a host which is not part of the same shared storage cluster? In the early days of Hyper-V, this process would look something like this (not in actual order):

  • The VM would be put into a saved state
  • The virtual hard disk (VHD) data would be copied to the new server along with any attached ISO images
  • The saved state data would be copied to the new location
  • The VM object is created on the destination, and then the VM is changed back to a running state.

Total time for transition (depending on VHD sizes): 40 mins to several hours

 

Now with SP1 for Windows 2008 R2, we have Quick Migration. While it is not as seamless as a Live Migration, Quick Migration allows the VM to stay running during the bulk of the transition. The new process looks something like this (not in actual order):

  1. Using VSS technology, Hyper-V creates a point-in-time snapshot of the VM. From this point until the end of the transition, the VM will be working off of a new differencing disk.
  2. VHDs and associated ISO images are copied to the destination host. The VM is still running normally during this part.
  3. The VM object is created on the destination server with all settings from previous host. The VM is still running normally during this part.
  4. Remaining data (active memory and the new differencing disk) are copied to the new host.

Total down time for transition: as little as 2 minutes for a VM with 4 GB of memory!!

About the author

Robert Borges

About Robert...

I have been in the IT industry since 1993 focusing mainly in networking. Though I got an early start as an amateur computer enthusiast, and wrote my first database app at age 12, I started my professional career working in the MIS department of one of the largest liquor distributors in the northeast. I started out there as a systems operator on the company’s two mainframe systems. From there I moved into PC support, and help design and implement the company’s first client-server network… This was back in the days of Win NT 3.51. I also worked on my first migration to NT 4.0 back then.

From there I went on to work with Novell 3.x and 4.x along with Windows domains and active directory environments. Working my way up from technician, to specialist, to administrator, and eventually all the way up to Sr. Engineer. I spent many years working for consulting firms, 9 of which I owned and operated my own firm.
Over the years, I have worked with (at an expert level) various versions of: Windows client and server operating systems (including Windows 7 and Windows Server 2008 R2);various virtualization technologies (Hyper-V, Virtual Server, Virtual PC, VMware, etc…); MS-SQL server 6.5- 2008 R2; Exchange 4-2010, and much more.

I am now Director of Information Systems at Bay State Integrated Technology focusing on cloud computing and IT service, with expertise in: IT Infrastructure & Architecture, IT Security, and Cloud Computing platforms & technologies (SaaS, PaaS, and IaaS).

I am in a constant state of learning about new products, and new versions of products. Many of which we end up implementing in lab environments and sometimes for our clients. I have a pretty broad range of expertise and experience. It is my goal to share some of this experience on this blog to help enrich the IT community.

Permanent link to this article: http://www.robertborges.us/2012/07/windows/windows-server-2008-r2/hyper-v-quick-migration/

1 ping

  1. Windows Server 2012 Feature: Share Nothing Live Migration in Hyper-V » Robert Borges Blog

    […] the hosts.  Hyper-V accomplishes this by starting off with a quick migration (see my prior post Introducing Quick Migration), but instead of coming down for the transfer of the active memory, this is transferred in small […]

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