Live Migration without shared storage

Windows Server 2012 also allows you to live migrate VMs between stand-alone Hyper-V hosts without the use of any shared storage. This scenario is also known as Live Migration Without Infrastructure (or Shared Nothing Live Migration), and the only requirements are that the two hosts must belong to the same Active Directory domain and that they must be using processors from the same manufacturer (all AMD or all Intel, for instance). When Live Migration without infrastructure is performed, the entire VM is moved from the first host to
the second with no perceived downtime. The process basically works like this (see Figure 2-7):

1. The Virtual Machine Management Service (VMMS; Vmms.exe) on the first host (where the VM originally resides) negotiates and establishes a Live Migration connection with the VMMS on the second host.

2. A storage migration is performed, which creates a mirror on the second host of the

VM’s VHD file on the first host.

3. The VM state information is migrated from the first host to the second host.

4. The original VHD file on the first host is then deleted and the Live Migration

connection between the hosts is terminated.

Live Migration connection Mirror VHD file Migrate VM state

Stand-alone host A Stand-alone host B

FIGURE 2-7 How Live Migration without shared storage works in Windows Server 2012.

Performing Live Migration

Live Migration can be performed from the GUI or using Windows PowerShell, but first you need to enable Live Migration functionality on your host machines. This can be done by using the Hyper-V console to open the Hyper-V Settings dialog box, as shown in Figure 2-8.

FIGURE 2-8 Enabling Live Migrations in Hyper-V Settings.

The tools that you can use to perform a Live Migration depend on the kind of Live Migration you want to perform. Table 2-3 summarizes the different methods for performing Live Migrations in failover clustering environments, Live Migrations using SMB 3 shares, and Live Migrations without infrastructure.

Windows Server 2012 gives you great flexibility in how you perform Live Migrations
of running VMs, including moving different VM components to different locations on the destination host when performing Live Migrations with or without shared storage. To see this, right-click a running VM in Hyper-V Manager and select Move to start the wizard for moving VMs. The first choice you make is whether to move the VM (and, optionally, its storage) to a different host or to move only the VM’s storage, as shown here:

Moving the storage of a running VM is called storage migration and is a new capability for Hyper-V in Windows Server 2012. We’ll look at storage migration later in Chapter 3, “Highly Available Easy-to-Manage Multi-Server Platform,” but for now, let’s say that you decide to move the VM by selecting the first option discussed previously. Once you’ve specified the name of the host you want to move the VM to, you’re presented with three options:

■ Moving all the VM’s files to a single location

■ Moving different files of the VM to different locations

■ Moving all the VM’s files except its VHDs

In each case, the target locations could be a shared folder on a Windows Server 2012 file
server or a local directory on the destination host:

If you choose the second option of moving different files of the VM to different locations as
shown here, you’re presented with additional options for specifying how to move the storage:

Choosing to move the VM’s items to different locations lets you specify which items you want to move, including the VHDs, current configuration, snapshot files, and smart paging files for the VM:

Additional wizard pages allow you to specify the exact way in which these items should be moved.