User manual MICROSOFT WINDOWS SERVER 2008 R2 WHITE PAPER

[. . . ] Windows Server 2008 R2 Hyper-VTM Live Migration White Paper Published: August 09 This is a preliminary document and may be changed substantially prior to final commercial release of the software described herein. The information contained in this document represents the current view of Microsoft Corporation on the issues discussed as of the date of publication. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information presented after the date of publication. Complying with all applicable copyright laws is the responsibility of the user. [. . . ] The storage handle for the VM's VHD files are moved to the destination physical computer. The destination VM is brought online on the destination Hyper-VTM server. Live migration produces significantly less downtime for the VM being migrated. This makes live migrations the preferred migration type when users must have uninterrupted access to the migrating VM. Because a live migration will complete in less time than the TCP timeout for the migrating VM, users will not experience any outage for the migrating VM during steps 3 and 4 of the migration. Windows Server® 2008 R2 Hyper-VTM supports both Quick Migration and live migration. Live Migration Architecture Hyper-VTM live migration is designed to move running VMs with no impact on VM availability to users. By pre-copying the memory of the migrating VM to the destination physical host, live migration minimizes the amount of transfer time of the VM A live migration is deterministic, meaning that the administrator, or script, that initiates the live migration can control which computer is the destination for the live migration. The guest operating system in the migrating VM is unaware that the migration is happening, so no special configuration for the guest operating system is needed. Windows Server 2008 R2 Hyper-VTM Live Migration Page #6 Requirements Hyper-VTM live migration has very similar requirements to Hyper-VTM Quick Migration. For organizations already using quick migration, the shift to using live migration should be simple. The physical hosts that will participate in live migration must be configured with Microsoft Failover Clustering Services as a Failover Cluster and must use shared storage. For example, to use live migration to move a VM from one Hyper-VTM physical host to another, both physical hosts must use processor(s) from the same manufacturer. It should be noted that there are no differences in storage requirements between Quick Migration and live migration. Below is a complete list of the requirements for Hyper-VTM live migration: Hyper-VTM live migration is supported on the following editions of Windows Server 2008 R2: o Windows Server 2008 R2 x64 Enterprise Edition o Windows Server 2008 R2 x64 Datacenter Edition Live migration is also supported on Microsoft® Hyper-VTM Server 2008 R2. Microsoft Failover Clustering must be configured on all physical hosts that will use live migration Failover Clustering supports up to 16 nodes per cluster The cluster should be configured with a dedicated network for the live migration traffic Physical host servers must use a processor or processors from the same manufacturer Physical hosts must be configured on the same TCP/IP subnet Physical hosts must have access to shared storage Recommendations and Notes: A clustered shared volume is recommended for VM storage in a cluster where live migration will be used. One live migration can be active between any two cluster nodes at any time. This means that a cluster will support number_of_nodes/2 simultaneous live migrations. For example, a 16-node cluster will support 8 simultaneous live migrations with no more than one live migration session active from every node of the cluster. A dedicated 1 Gigabit Ethernet connection is recommended for the live migration network between cluster nodes to transfer the large number of memory pages typical for a virtual machine. The cluster configurations that have been validated by vendors can be found through the listings in the FCCP program under the heading of The Microsoft Support Policy for Windows Server 2008 Failover Clusters at this URL: http://support. microsoft. com/default. aspx?scid=kb;ENUS;943984 How Live Migration Works The live migration process is designed to move a running VM from the source physical host to a destination physical host as quickly as possible. A live migration is initiated by an administrator through one of the methods listed below. The speed at which the process completes is partially dependent on the hardware used for the source and destination physical computers, as well as the network capacity. [. . . ] In anticipation of periods of greater demand (such as daily peak usage, quarter end, or yearend processing), the offline physical host can be powered back on and the VM load can be redistributed using live migration. The Hyper-VTM live migration feature is integrated with Windows Server 2008 R2 Hyper-VTM and no separate licensing or product installation is involved. In fact, any configuration which worked with Quick Migration and also includes processors of the same type will support live migration. Windows Server 2008 R2 Hyper-VTM Live Migration Page #16 Figure 5 ­ Increasing Consolidation Ratio Deploying Live Migration Because Windows Server 2008 has eased the configuration process for Failover Clustering, deploying live migration is easy. First, complete the planning necessary to determine how many cluster nodes you will implement. [. . . ]