Of all the different technologies at Microsoft, there's no doubt that none is evolving faster than System Center Virtual Machine Manager (VMM). You can manage your entire virtualization infrastructure with VMM, including both Microsoft Hyper-V and VMware ESX Server virtual machines (VMs). You can also create and deploy new VMs as well a manage VM states and storage. The new VMM 2008 R2 release is designed to take full advantage of the recent Windows Server 2008 R2 and Hyper-V R2 improvements. Here are the top ten new features in VMM 2008 R2.

1. Live Migration—Without a doubt, the most important new feature in VMM 2008 R2 is Live Migration. This feature is the equivalent of VMware's VMotion; it lets you move a virtual machine (VM) between Hyper-V hosts with no downtime. Live Migration requires Windows Server 2008 R2 or Hyper-V Server 2008 R2.

2. Support for the Clustered Shared Volume (CSV) file system—To support Live Migration, Microsoft added the CSV file system to Server 2008 R2. CSV lets multiple hosts in a cluster simultaneously access a shared LUN. The CSV feature also facilitates easier storage management by letting you store multiple VM files on the same LUN.

3. Support for hot add/removal of storage—VMM 2008 R2 supports the hot addition and removal of storage on Hyper-V VMs. This new feature lets you add Virtual Hard Disks (VHDs) to running VMs and remove VHDs from running VMs with no downtime.

4. Rapid provisioning—The new rapid provisioning feature lets administrators utilize underlying SAN technologies for cloning VM files, then combines the cloned image with the ability to supply a VMM template for customizing the guest OS. Rapid provisioning doesn't have a UI. Instead, it's driven by PowerShell commands.

5. Quick Storage Migration—VMM 2008 R2's Quick Storage Migration lets you move Hyper-V VM storage between different LUNs with minimal downtime. Quick Storage Migration is particularly useful for taking advantage of CSV storage and consolidating your VM files on a shared LUN. Quick Storage Migration requires between 20 seconds and a couple of minutes of downtime, depending on the size of your VMs and the performance of your storage subsystem.

6. Support for VMware Storage VMotion—Closely related to Quick Storage Migration is support for VMware Storage VMotion. Storage VMotion lets you move an ESX Server's VM files between LUNs with no downtime. Like VMM 2008's support for VMotion, support for Storage VMotion requires VMware vCenter Server.

7. Support for Veritas Volume Manager—Another new storage related enhancement in VMM 2008 R2 is built-in support for Veritas Volume Manager. VMM 2008 R2 recognizes Veritas Volume Manager disks as a cluster disk resource.

8. Enhanced iSCSI SAN support—VMM 2008's support for iSCSI SANs has been improved so that multiple LUNs can be bound to each iSCSI target. This capability provides broader industry support for more iSCSI SAN hardware options.

9. Maintenance mode—Maintenance mode lets you specify that you're going to perform some type of hardware or OS maintenance to a Hyper-V host. When you use maintenance mode on a Hyper-V host, all the VMs that are Live Migration–enabled are migrated to another host. VMs that aren't configured for Live Migration automatically have their state saved.

10. Host compatibility checks—One of the limitations of moving VMs between hosts is the fact that the hosts must have compatible processors. For example, you can't move a VM from a Hyper-V host that uses an Intel CPU to a Hyper-V host that uses an AMD CPU. VMM 2008 R2's host compatibility checks verify that the CPUs of different hosts are compatible for actions such as Live Migration and Quick Storage Migration.