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Planning for the VMM Library

The Virtual Machine Manager (VMM) library is a catalog of resources you can use to create and configure virtual machines in VMM. The library contains files stored on library shares, and it contains operating system, hardware, and template configurations stored in the VMM database. Library resources are added, created, used, and managed in Library view.

To be used in VMM, file-based resources must be added to the library by storing the files on a library share of a library server.

Virtual machine templates, hardware profiles, and guest operating system profiles are used in creating uniform virtual machines. These configurations are managed in Library view, but are stored in the VMM database and not represented by physical configuration files.

Virtual machines that are not in use and stored in the library are displayed in Library view. However, the configuration file (.vmc) and hard drive file (.vhd) for a stored virtual machine are not indexed during a refresh of the library because these files cannot be used to create or configure new virtual machines. For more information about library refreshes and indexing library files, see the "About Library Refreshes" topic in VMM Help (

Virtual Machine Manager does not support file servers configured with the case-insensitive option for Windows Services for UNIX (Network File System case control is set to Ignore). For more information about Network File System case control, see article 276015 in the Microsoft Knowledge Base (

Library Servers

By default, the VMM contains a single library server and a single library share, which Setup creates on the VMM server. The VMM server always remains the default library server.

During Setup, you specify the name, location, and a description for the default library share on the library server. You can accept the default settings or specify your own settings.

After Setup is complete, you cannot remove or relocate the default library server or its library share. So give careful consideration to its location before installing the VMM server.

The default library server might be the only library server you ever need. However, you can add more library servers and shares based on your current business needs and objectives, and to scale out as your virtual environment grows.

If you use a SAN, it is a best practice to have a library server on the same SAN as the hosts that use the library. By doing so, the library server and the hosts can all access the same logical unit numbers (LUNs) on the SAN and you make faster file transfers.

If you connect to a library server from virtual machine hosts across a LAN network, your library server should be as close to the hosts as possible on the network. It is a best practice to connect all computers in a VMM configuration with at least a 100-MB Ethernet connection. Using a gigabit Ethernet connection will improve performance. Using a gigabit connection, combined with a more powerful processor than the recommended processor on the VMM server, will further improve performance.

Library Groups

As you add more library servers, you can create library groups to help you organize library servers in whatever way works best. You can also use library groups to align your library servers with the host groups that use the resources on the library server. It is a best practice to align each library server with the host group that uses the resources on the library server.

The library group Properties dialog box makes this alignment easy to do by displaying the host groups in the Library group drop-down list. For more information about adding a library group, see the "How to Modify the Properties of a Library Server" topic in VMM Help (

Aligning library servers with host groups is especially beneficial when your library server is connected to the same SAN as the hosts in a host group. By using descriptive host group and library group names, and then aligning them, you can readily identify which hosts and library servers are connected to the same SAN and therefore can take advantage of faster file transfers on the SAN.

Distributed Resources

For geographically-disperse organizations, VMM supports the use of distributed VMM libraries. For example, if you have branch offices in multiple locations, users in those locations can build virtual machines by using resources from a local library server instead of copying multi-gigabyte files from a centralized library server over a wide area network (WAN). Having distributed VMM libraries can also help ensure the availability of files during WAN outages or server failures.

Library Share Permissions

To create a new virtual machine and store it directly into a library share by using the New Virtual Machine Wizard, the VMM administrator must have Read permission on the library share.

See Also