the same authentication configuration. While there is more work involved in the use
of Kerberos authentication, the additional flexibility makes the additional work
worthwhile and definitely recommended. To configure the authentication type to use
from PowerShell, use the Set-VMHost cmdlet and set
VirtualMachineMigrationAuthenticationType to either CredSSP or Kerberos.
Initiating Simultaneous Migrations Using PowerShell
The Move-VM PowerShell cmdlet can be used to trigger Live Migrations. To trigger
multiple Live Migrations, the following can be used:
Get-VM blank1,blank2,blank3 | Move-VM -DestinationHost savdalhv02
The problem is that this would live-migrate blank1, and once that is finished, it would
live-migrate blank2, then blank3, and so on. It is not performing a simultaneous Live
Migration, which is possible in Windows Server 2012 and above.
One solution is to use the -parallel option available in PowerShell v3 workflows to
trigger the Live Migrations to occur in parallel, as in this example:
Workflow Invoke-ParallelLiveMigrate
{
$VMLIST = get-vm blank1,blank2,blank3
ForEach -Parallel ($VM in $VMLIST)
{
Move-VM -Name $VM.Name -DestinationHost savdalhv02
}
}
Invoke-ParallelLiveMigrate
The Live Migrations will now occur in parallel. Make sure that your Hyper-V hosts are
configured with the needed setting for the number of concurrent Live Migrations you
wish to perform on both the source and destination Hyper-V hosts.
Windows Server 2012 R2 Live Migration Enhancements
Windows Server 2012 R2 introduced performance improvements to Live Migration by
allowing the memory transferred between hosts to be compressed or sent using SMB.
The option to use compression means less network bandwidth and therefore faster
Live Migrations, but additional processor resources are used to compress and
decompress the memory. The option to use SMB is targeted to environments that
have network adapters that support remote direct memory access (RDMA), which
gives the fastest possible transfer of data with almost no server resource usage
(compression is not used; it’s not needed). By selecting SMB when network adapters
support RDMA, you leverage the SMB Direct capability, which gives the best possible
performance. Do not select SMB if your network adapters do not support RDMA.
By default, the compression option is selected for Live Migration, but it can be
changed as follows: