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Moving from Virtual Server to Virtual Machine Manager

This topic provides the practical information that Virtual Server administrators need in order to transition smoothly to managing their existing hosts and virtual machines in System Center Virtual Machine Manager 2007 (VMM). For a quick reference to specific tasks to perform when you add your host to VMM, see Checklists: Adding an Existing Host to Virtual Machine Manager.

This topic does not provide information on how to add hosts to VMM or plan the network topology for your virtual environment. This is also not a general introduction to the features of VMM. For those topics, see the links in Related Resources.

What to Expect After Adding a Host to VMM

When you add an existing Virtual Server-based host to VMM, VMM discovers all virtual machines that the host is managing, which lets you begin managing the virtual machines in VMM immediately. However, certain capabilities and features of virtual machines are implemented differently in VMM than in Virtual Server. To take full advantage of the capabilities of VMM, you must update a few configurations.

All virtual machines that are registered in Virtual Server are added to VMM and can be viewed and managed in Virtual Machines view in the VMM Administrator Console. To register virtual machines that were not registered on the host, you can update the properties of the host. For more information, see "How to Register Virtual Machines on a Host" (

Unsupported Disk Configurations for Virtual Machines

The following disk configurations for virtual machines are either not supported or not used by VMM:

  • Multiple versions of the same .vhd attached to a single virtual machine. If you are using differencing disks to maintain different versions of the same virtual machine in Virtual Server, and you attach different versions of the same .vhd to a single virtual machine, data will be lost if one of the hard disks is removed from the virtual machine.
  • Undo disks. Undo disks are not used and not supported in VMM. Instead of undo disks, checkpoints are used to restore a virtual machine to a previous state in VMM. The presence of undo disks does not prevent VMM from discovering a virtual machine. However, before you can manage the virtual machine in VMM, you must either merge or discard the undo disks. The Disable undo disks action in Virtual Machines view is provided for this purpose. For more information, see "How to Disable Undo Disks for a Virtual Machine ( For information about checkpoints, see "About Virtual Machine Checkpoints" (

The Work Area

Use the buttons beneath the navigation pane in the VMM Administrator Console to display the views you work in when creating, migrating, and managing virtual machines. The following table lists the tasks for administering hosts and virtual machines in each view. For a full discussion of the VMM Administrator Console, see "Using the VMM Administrator Console" (

View Tasks

Virtual Machines

View and manage the virtual machines on your hosts. When you added the host, all virtual machines that were registered in Virtual Server were discovered and added to this view.

Create, deploy, run, remove, and store virtual machines. Create checkpoints for virtual machines.

Virtual machine statuses and actions are similar to those used in Virtual Server, with some differences. See "Actions Performed on Virtual Machines in VMM" (


Add, remove, manage, and update the configurations of managed hosts. Create host groups to organize hosts and virtual machines. Configure virtual machine self-service to enable users to create and manage their own virtual machines based on templates that you provide.


Work with ISO images, scripts, and virtual hard disks to create virtual machines.

Create virtual machine templates, hardware profiles, and guest operating system profiles for use when creating virtual machines.

Store virtual machines that are not in use.


Monitor, retry, and cancel jobs. View detailed job status, including status for each step in a job and an audit list of changes made to objects in VMM.


Managed Computers-- Find out the status of managed computers. Manage the Virtual Machine Manager agents on hosts and library servers. Update agents. Reassociate agents with the current VMM server. Remove an agent or a managed computer role.

Self-Service--Add and remove Web servers used in virtual machine self-service. For more information about self-service, see "About Virtual Machine Self-Service" (

VMM Settings:

  • Virtual machine placement defaults--Set the placement goal and resource importance for rating hosts during virtual machine placement.
  • VMRC--Configure Virtual Machine Remote Control (VMRC), which is used to connect to virtual machines from the VMM Administrator Console.


Use VMM reports to track the resource allocation and utilization on hosts and virtual machines and identify candidates for virtualization: Virtualization Candidates, Virtual Machine Allocation, Virtual Machine Utilization, Host Utilization, and Host Utilization Growth. For more information, see "Report Descriptions" (

Reporting view is not displayed until you deploy the Server Virtualization Management Pack in System Center Operations Manager 2007 and identify the reporting server in VMM. For more information, see the Server Virtualization Management Pack Guide (

Feature Differences for Virtual Machines

Virtual machine and host configurations are preserved in VMM during discovery. However, a few features are handled differently in VMM than in Virtual Server:

Virtual machine configuration files.   In Virtual Machine Manager, a virtual machine's configuration is stored in the VMM database instead of a virtual machine configuration (.vmc) file. This enables VMM to efficiently recreate the virtual machine's configuration each time that the virtual machine is migrated to a different host. The .vmc file created by Virtual Server is not used by VMM.

When Virtual Machine Manager creates a virtual machine, all of the virtual machine's configuration files—including virtual hard disks (.vhd files), virtual floppy disks (.vfd), and the virtual machine configuration file (.vmc)--are stored in a folder with the name of the virtual machine. Virtual network configuration files (.vnc) are stored on a path specified in the host properties.

Actions performed on virtual machines.   The basic set of actions for virtual machines is very similar to those in Virtual Server, although some are not available because of features that are implemented differently (for example, without undo disks, there is a smaller set of options for stopping a virtual machine) and additional features, such as creating checkpoints. For a full reference to the actions performed on virtual machines, see "Actions Performed on Virtual Machines in VMM" (

Unlike in Virtual Server, when you use the Remove action to remove a virtual machine from Virtual Machine Manager, the virtual machine's configuration files and virtual hard disks are deleted, and you cannot resume using the virtual machine by registering it in Virtual Server. If you want to retain the virtual hard disks and other configuration files for the virtual machine, store the virtual machine in the library instead of removing the virtual machine. If you want to use the virtual hard disks in other virtual machines, create a virtual machine template based on the virtual machine or its virtual hard disks. For more information, see "How to Store a Virtual Machine in the Library" ( and "Creating Virtual Machine Templates " (

Virtual Server start and stop actions.   Virtual Server start and stop actions that are configured for a virtual machine are retained during discovery. However, the start and stop actions and the Virtual Server "run-as" account credentials must be reset each time the virtual machine is migrated to a different host.

Connecting to virtual machines from the VMM Administrator Console.   VMM uses Virtual Machine Remote Control (VMRC) to connect to virtual machines from the VMM Administrator Console and from the VMM Self-Service Portal. Port 5900 is assigned VMRC by default. You can specify a different port when you add a host to VMM, or you can update the VMRC configuration through VMM settings. For more information, see "How to Configure VMRC Access to Virtual Machines" (

Use Checkpoints Instead of Undo Disks to Recover a Virtual Machine to a Previous State

Instead of the undo disks used in Virtual Server, "checkpoints" are used in VMM to restore a virtual machine to a previous state. Each checkpoint saves the state of each virtual hard disk attached to a virtual machine, as well as all of the hard disk's contents, including application data files. You can create multiple checkpoints for a virtual machine. For more information, see "About Virtual Machine Checkpoints" (

Use Virtual Machine Self-Service to Limit Access to Virtual Machines

In Virtual Machine Manager, all VMM administrators have access to all virtual machines and their associated files. A virtual machine's owner also has access to his own virtual machines and their associated files.

If you are controlling access to individual virtual machines in Virtual Server by updating Access Control Lists (ACLs) on the folders that hold the virtual machine configuration files, the entire set of ACLs will be overwritten when you migrate the virtual machine to a different host or change the owner of the virtual machine in VMM. In both cases, VMM recreates the Access Control List. Any permissions that have been assigned outside VMM are lost.

Virtual machine self-service provides a better way to exercise precise control over what users can and cannot do with their own virtual machines. In virtual machine self-service, users can manage, and optionally create, their own virtual machines within a restricted environment. Self-service users create their virtual machines from templates that the administrator provides, and they can only see and operate their own virtual machines.

Self-service access is granted through self-service policies, which can be created for individual users or for groups. Through virtual machine permissions in the self-service policy, you can exercise fine control over what the self-service user or group can do with their own virtual machines. For information about the specific permissions that you can assign, see "How to Grant Virtual Machine Management Permissions to Self-Service Users" ( You also can place quotas on the number of virtual machines that a policy allows a user or group to deploy. For more information, see "About Self-Service Policies" (

The self-service policies are associated with host groups, and self-service users' virtual machines are deployed automatically to the most suitable host within the host group.

For more information about virtual machine self-service, see "About Virtual Machine Self-Service" (

Monitor Jobs, Not Alerts

In VMM, administrators monitor detailed job status instead of alerts to find out the status of operations. Jobs view of the VMM Administrator Console displays a complete listing of VMM jobs, which you can search, sort, filter, and group. The job details provide the status of each step in a job and an audit trail of changes that are made to objects in VMM.

To monitor the progress of your own jobs while you work in any view, open the Jobs window. To open the Jobs window, click the Jobs button on the VMM toolbar.

For more information, see "How to Monitor Jobs" (

Configuration Updates to Support Virtual Machine Migration

The migration of virtual machines between hosts requires some configuration updates on hosts. You should also follow some best practices to help ensure the most accurate host ratings during virtual machine placement.

Configure Standard Virtual Networks on All Hosts

To support virtual machine migration, you should configure standard virtual networks on all hosts. When an existing host is added to VMM, the virtual networks that were configured in Virtual Server are preserved, so the network connections of virtual machine continue to work on the virtual machine's current host. However, when you migrate a virtual machine to a different host, the virtual network adapters on the virtual machine will be left in a not connected state after the migration if the target host does not have virtual networks equivalent to those that the virtual network adapters were connected to on the previous host. During migration, VMM attempts to connect the virtual network adapters on the virtual machine with equivalent virtual networks on the target host based on the virtual network name as well as the virtual network description.

To resolve this issue, you can specify standard network descriptions -- such as CORPNET -- for the virtual networks that are configured on all hosts. When a virtual machine is migrated, if the target host does not include a virtual network that has the same network name as a virtual network in the virtual machine's configuration, VMM checks for a matching virtual network description. For more information, see "Adding and Configuring Hosts" ( 103440). For information about configuring network access for a virtual machine, see "How to Add and Configure Network Adapters for a Virtual Machine" (

Configure Default Virtual Machine Paths on All Hosts

To enable successful automatic placement of virtual machines on the most suitable host in a host group, you must define a default virtual machine path for each volume that will store virtual machine configuration files on a host. For more information, see "How to Set Placement Options for a Host" (

Two features of VMM use automatic placement. In virtual machine self-service, the virtual machines owned by self-service users are deployed automatically on the most suitable host in the host group that contains the user's self-service policy. Automatic placement also occurs when you use the drag-and-drop method to migrate a virtual machine to a host group in Virtual Machines view. For more information, see "About Virtual Machine Self-Service" ( and "How to Migrate a Virtual Machine to a Different Host" (

When you use a wizard to deploy or migrate the virtual machine, you can use Virtual Machine Manager's host ratings to select a suitable host and then specify any path on the host that has sufficient disk space available to meet the virtual machine's disk requirement. However, during automatic placement, VMM attempts to copy the virtual machine's configuration files to the volume that has the most disk space available on the host that has the highest rating. If no default virtual machine path is configured for the preferred volume, the migration fails. For more information, see "About Virtual Machine Placement" ( and "How Virtual Machine Manager Rates Hosts" (

Preparing to Create New Virtual Machines in VMM

Before you start creating virtual machines in Virtual Machine Manager, you need to add your existing resources to the Virtual Machine Manager library and create virtual machine templates from the virtual hard disks to use as sources for virtual machines.

The Virtual Machine Manager library is used to centrally manage all resources that you use to create and configure virtual machines. Until you set up your library servers and library shares, the files will not be indexed in VMM and will not be available for VMM operations.

To Prepare to Use Your Existing Resources

To prepare to use your existing resources in VMM, perform the following tasks:

  • Add all files that you use to create and configure virtual machines to the library. You will not be able to use your ISO images, scripts, and virtual hard disks to create new virtual machines until you add them to the library. To add files to the library, you need to deploy a VMM agent on the server that contains the shares and designate the shares as library shares. To do this, add the server as a library server, and specify the library shares to be indexed in VMM. For a procedures full set of procedures, see "Adding File-Based Resources to the Library" ( For general information about the library, see "About the Virtual Machine Manager Library" (
  • Create virtual machine templates from the virtual hard disks that you use to create virtual machines. A virtual machine template provides a standardized group of hardware and software settings that can be used repeatedly to create new virtual machines configured with those settings. For more information, see "Creating Virtual Machine Templates in VMM" (
    As you settle into creating virtual machines in VMM, you will want to explore the use of hardware profiles and guest operating system profiles to import collections of standard settings into templates and virtual machines. For more information, see "About Hardware Profiles" ( and "About Guest Operating System Profiles" (

Best Practices for Managing Your Resources in VMM

Use the following guidelines to ensure the availability of file-based resources in the VMM library and make the best use of your library servers:

  • When you plan your network topology, provide the fastest possible connections between your library servers and the hosts that use their resources. If you use a SAN, have a library server on the same SAN as the hosts. For more information, see "Planning for the VMM Library" (
  • Use your library servers to store virtual machines that are not in use so that the virtual machines do not consume disk space on the host.
  • Include installing operating system and other updates on templates in your scheduled management tasks. Because templates, unlike virtual machines, are not run, the templates do not automatically receive updates and through Microsoft Updates. To ensure that the systems and software on the templates is secure and up to date, you must maintain the templates as you would a computer.
  • Use the Remove actions in Library view to remove files, library shares, and library servers. When you use a Remove action, VMM checks virtual machines and templates for dependencies on any of the resources that you are removing. You must remove any dependencies before completing the job.
  • Instead of moving configuration files manually between hosts and library servers, and then registering virtual machines in Virtual Server, use VMM to deploy, migrate, and store virtual machines. This ensures that the configuration files are moved together and the paths are updated in VMM.
  • If you move files within the library—from one share to another or from one path to another within the same share—the paths are updated in VMM during the next library refresh. By default, the library is refreshed once each hour. To see the results immediately, manually refresh the library share. For more information, see "How to Refresh a Library Share" (

Related Resources

Resource Description

Planning for Hosts

Planning for Host Groups

Planning your network topology and your use of host groups to manage hosts and virtual machines

Adding and Configuring Hosts

Procedures for deploying the VMM agent and adding hosts to Virtual Machine Manager

Checklist: Adding An Existing Host to Virtual Machine Manager

A checklist of tasks to perform after adding an existing host to VMM

Planning for the VMM Library

Planning your network topology to support fast connections between library servers and the hosts that use their resources

Creating Virtual Machines in Virtual Machine Manager

A tutorial for getting started creating virtual machines, a full set of procedures for creating virtual machines from different sources, and procedures for creating templates.

Actions Performed on Virtual Machines in VMM

A reference list of the actions that can be performed on virtual machines.

Virtual Machine Manager Help

Feature descriptions, configuration overviews, how to perform tasks in the VMM Administrator Console