View Microsoft LiveMigration dynamic migration technology (1)

Live Migration: dynamic Migration is one of the most anticipated new features in Windows Server 2008 R2 Hyper-V. The following describes in detail the dynamic migration of Windows Server 2008 R2 Hyper-V, including how to run virtual machines during dynamic migration, dynamic migration plays an important role in several specific situations and requires the execution of dynamic migration.

Overview

Live Migration, dynamic Migration is a new feature of Windows Server 2008 R2 Hyper-V and Microsoft Hyper-V Server R2. Using Hyper-V dynamic migration, you can move a running Virtual Machine from one Hyper-V physical host to another without any service interruption or downtime.

Hyper-V can move virtual machines running without downtime, which brings more flexibility and value:

Provides better Agility: data centers and multiple Hyper-V physical hosts will be able to use the performance of users, if scaling and optimization are not affected, move the running virtual machines to the best physical host.

Reduce costs and improve production efficiency: data centers and multiple Hyper-V physical hosts can maintain these systems in a more controllable manner and arrange their maintenance within normal operation time. Dynamic migration can keep virtual machines online. This greatly improves production efficiency for users and administrators. The data center will also be able to reduce energy consumption by adding a strong merging ratio and disabling idle physical hosts during a period of demand decline.

Comparison Between Live Migration for dynamic Migration and Quick Migration for Quick Migration

Quick Migration is also a common feature of Windows Server 2008 Hyper-V and Windows Server 2008 R2 Hyper-V. Both dynamic migration and fast migration can move the running Virtual Machine from one Hyper-V physical host to another, their main difference is that Quick Migration, storage, and recovery of virtual machines require downtime. Dynamic Migration of Live Migration uses different mechanisms to move virtual machines to new physical computers.

1. All VM memory pages are transferred from the source Hyper-V physical host to the target Hyper-V physical host. During these operations, modifications to any VM Memory Page are tracked.

2. When Pages are modified to the physical computer in the target place during the first step.

3. The storage handle of VHD files on the virtual machine is moved to the target physical computer.

4. The target virtual machine is online on the Hyper-V server.

Dynamic migration greatly reduces the downtime of Virtual Machine migration. This makes dynamic migration the first choice for users to migrate virtual machines when they need to work continuously. Because the completion time of dynamic migration is much less than the TCP intermittent time during the migration process of the virtual machine, you can complete steps 3rd to 4th of the migration without being affected.

Windows Server 2008 Hyper-V released in 2008 supports fast migration, while R2 of Windows Server supports both fast migration and dynamic migration. So the main innovation of the R2 version of dynamic migration.

Dynamic migration Architecture

Hyper-V dynamic migration is designed to move virtual machines without affecting users' use of virtual machines. By pre-copying the memory of the migrated virtual machine to the target physical host, dynamic migration greatly reduces the transfer time in the process of a mobile virtual machine, at the same time, the administrator or script can control which computer will be the target computer for the migration when starting the dynamic migration. During the running of the system, the customer does not feel that the migration is in progress. Therefore, it is necessary for the customer to have no special configurations.

Requirements:

Hyper-V dynamic migration has similar requirements as Hyper-V rapid migration. For organizations that are already using quick migration, it is very easy to switch to dynamic migration. During dynamic migration, the Microsoft failover cluster service must be configured as a Failover cluster for physical host participation, and shared storage must be used. In addition, physical hosts must use the same type of processors. For example, to use dynamic migration to migrate a virtual machine from a Hyper-V physical host to another, the two physical hosts must use the same manufacturer's processor. At this point, both dynamic migration and quick migration have the same requirements.

The following is a complete list of requirements for Hyper-V dynamic migration:

Hyper-V dynamic migration supports Windows Server 2008 R2 of the following versions:
Windows Server 2008 R2 x64 Enterprise Edition
Windows Server 2008 R2 x64 Datacenter Edition

Hyper-V Server 2008 R2 also supports dynamic migration
During dynamic migration, all physical hosts must be set as Microsoft failover clusters.
Failover clusters support 16 nodes per cluster
The cluster should configure a dedicated network for dynamic migration
Physical host servers must use processors of the same manufacturer
The same TCP/IP subnet must be configured on the physical host.
The physical host must be able to access shared storage.

Suggestion:

We recommend that you use cluster shared volumes for VM storage during dynamic migration.
A dynamic migration can be very active between any two cluster nodes at any time. This means that a cluster supports two dynamic migration nodes at the same time. For example, a 16-node cluster supports up to eight dynamic migration tasks at the same time when each node in the cluster is activated dynamically.
Configure a dedicated Gigabit Ethernet network for dynamic migration of large volumes of storage pages transmitted between Vm instances in a cluster node.

How dynamic migration works

The goal of the dynamic migration process is to move a running Virtual Machine from a source physical host to the target physical host as soon as possible. A dynamic migration is started by the Administrator using one of the methods in the list. The speed at which this process is completed depends on the hardware usage and network capacity of the source and target computers. The following are three methods of dynamic migration startup:

A. The administrator can start A dynamic migration on the Failover cluster management console.

B. Virtual Machine administrators manage physical hosts. When they are set to support mobile migration, the Management Console of Virtual Machine manager can start a dynamic migration.

C. a wmi or PowerShell script can start a dynamic migration.

Any customer Operating System Supported by Hyper-V dynamic migration. After a dynamic migration is started, the following process will occur:

1. dynamic migration startup

Startup is the first phase of dynamic migration. The Source Physical host establishes a TCP connection with the target physical host. This connection is used to transmit VM settings data to the target physical host. Based on the set data, the basic virtual machine is created on the target physical host, and the memory is allocated to the target virtual machine.

Figure 1 installation of dynamic migration