Migrating a Virtual Server 2005 R2 Host to Hyper-V
Migrating from Virtual Server 2005 R2 SP1 to Hyper-V is a multistep process, but the steps may vary based on the current configuration of your Virtual Server host. From previous chapters, you know that to run Hyper-V, you must have either Windows Server 2008 64-bit or Microsoft Hyper-V Server 2008. Unless the current Virtual Server 2005 R2 SP1 installation is running on the Windows Server 2008 64-bit operating system, you will first need to create a new installation of Windows Server 2008 x64 or Microsoft Hyper-V Server 2008.
If the Virtual Server host is currently running on Windows Server 2008 x64, it is possible to back up the host, uninstall Virtual Server, install the Hyper-V role, and then migrate the virtual machines. This method allows you to use the same hardware during the migration without having to copy virtual machine files to another computer, but it requires the existing Virtual Server and the virtual machines to be taken offline, so users will experience downtime. It also means that if something goes wrong, the recovery process will not be quick or painless. To minimize downtime on the host and the virtual machines, a better approach is to build a new Hyper-V server and migrate the virtual machines to the new server. You will gain several advantages by using this approach:
The flexibility to migrate virtual machines when needed
The ability to size the hardware to meet the requirements
No downtime for the existing Virtual Server host
The consolidation of multiple Virtual Server hosts to a single Hyper-V server or cluster of hosts
In addition, if something goes wrong during the migration process, the virtual machines still exist on the Virtual Server host and can be rebooted quickly.
The host migration process discussed in the following sections focuses on the side-by-side migration approach versus the migrate-in-place approach. The steps in the process include developing the specification for the Hyper-V server hardware, building the Hyper-V servers, and migrating the configuration. When you have completed the migration, you will be able to add any new features or capabilities available in Hyper-V.
Developing the Hyper-V Server Specification
The first step in the process is discovering and documenting the configuration of the Virtual Server 2005 R2 SP1 environment so that you can determine the minimum required Hyper-V hardware configuration. This involves determining the current hardware specification for memory, disk storage, networking, and processor. In addition, collect the number of virtual networks currently configured on the Virtual Server host. When you have collected this information, you can start developing the Hyper-V server specification. Use the following guidelines to determine the specification.
Hyper-V memory configuration should include memory reserved for the parent partition—typically a minimum of 1 gigabyte (GB) of RAM, virtual machine memory—the size of the memory of each virtual machine plus overhead calculated by adding 32 MB for the first gigabyte (GB) of RAM and then 8 MB for each additional gigabyte of RAM, and memory for the predicted number of concurrent VMConnect.exe sessions on the host at 20 MB each. It is always a good idea to add additional memory for expansion for temporary purposes (1 to 2 GB of RAM). At a minimum, you should make sure the Hyper-V server has as much memory as the current Virtual Server host.
Disk storage can involve many choices, including disk drive speed, disk drive size, RAID configuration, controller cards, and so on. Focusing on just the amount of storage you will need, the server requires space for the parent partition operating system; space for each virtual machine’s virtual hard disk (VHD), the maximum defined size of the VHD; space for saved-state files, which will vary based on the amount of RAM in the virtual machine; space for snapshots, which will vary based on the number of snapshots planned; and space for additional files such as CD or DVD images. At a minimum, you will need the amount of storage space that is currently used on the Virtual Server host, plus additional space for snapshots if you plan to use them.
Networking configuration involves the needs of the parent partition, interfaces for iSCSI communications, interfaces for clustering if the Hyper-V server is a member of a host cluster, and interfaces for the required number of virtual networks. The Hyper-V server should include a minimum of one 1-gigabit Ethernet card reserved for parent partition management purposes, one 1-gigabit Ethernet card for iSCSI communications (if iSCSI will be used), two 1-gigabit Ethernet cards for cluster communications (if a member of a host cluster), and one 1-gigabit Ethernet card for each required external virtual network.
Processor configuration involves the needs of the parent partition, each virtual machine, and reserve for unexpected peaks in performance. The Hyper-V parent partition should have a minimum of one processor core reserved for its use to manage shared parent partition resources; each virtual machine should have a minimum of a single processor core; and a reserve amount of processing (one or more cores) should be included for peaks in performance and possible expansion. Virtual machines in Virtual Server 2005 R2 SP1 could have only a single processor. With Hyper-V, each virtual machine can have up to four virtual processors (depending on the operating system). If any virtual machines currently running under Virtual Server are utilizing high amounts of processing power, there is an opportunity to add virtual processors during the migration. Be sure to account for any additional processors you may need during the sizing process.
When you have identified the Hyper-V configuration you will require and have purchased and assembled the hardware, you are ready to install Hyper-V on the system. Chapter 4, “Hyper-V Installation and Confi guration,” goes into detail about how to install Hyper-V on the hardware and outlines the post-installation configuration changes that you should make.
Migrating Virtual Networks
After you have completed the default installation and optimization, you are ready to migrate the current configuration of the Virtual Server 2005 R2 SP1 virtual networks to the Hyper-V server. This is a manual process and involves recreating the required virtual networks that existed on the Virtual Server host on the Hyper-V server. In order to do this, you must determine the mapping of the existing virtual networks to physical adapters or loopback adapters (in the case of internal networks). When you have identified the mapping, collect the TCP/IP settings for the network adapter so that the subnet can be identified. This will allow you to determine which physical network adapter must be used in the Hyper-V server when the external virtual networks are recreated or how many internal or private virtual networks must be created.
The next step is recreating the external virtual networks on the new Hyper-V server to the correct physical network adapter using the mapping you identified. Although the virtual network name does not have to be the same as it was on the Virtual Server host, it is a good idea to use the same name to minimize any confusion. After the external virtual networks are completed, recreate any required internal or private virtual networks.
If the Hyper-V server was configured with additional physical network adapters to expand the number of available external virtual networks, now is the time to configure these. Remember to use the established naming convention for virtual networks.