Read Windows Server 2008 R2 Unleashed Online
Authors: Noel Morimoto
Machines to start the virtual machine and install the operating system.
Once the operating system is installed, Live Migration can be used to move the cluster
from one node to another.
Quick Migration and Live Migration
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Deploying Existing Virtual Machines on CSV Failover Clusters
If the LUN provisioned as a CSV disk in the cluster contains existing virtual machine
images, these can be made highly available. You can also copy any virtual hard disk to the
CSV volume and make it highly available:
1. On one of the cluster nodes, open Failover Cluster Management.
2. Expand the cluster and select Services and Applications.
3. Right-click Services and Applications and select Configure a Service or Application.
This will open the High Availability Wizard.
4. Click Next on the Before You Begin page.
5. On the Service or Application page, click Virtual Machine and click Next.
6. Select the virtual machine(s) to be made highly available and click Next.
7. Review the Summary page in the wizard and click Finish.
8. Select the virtual machine in the Service and Application pane and click Start Virtual
Machines in the Actions pane.
Performing a Live Migration
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The virtual machine runs on one of the cluster nodes, known as the owner. When a Live
Migration is performed, multiple steps are performed. These steps can be broken down
into three stages: preflight migration, virtual machine transfer, and final transfer/startup
of the virtual machine.
The first step in Live Migration occurs on the source node (where the virtual machine is
37
currently running) and the target node (where the virtual machine will be moved) to
ensure that migration can, in fact, occur successfully.
The detailed steps of Live Migration are as follows:
1. Identify the source and destination machines.
2. Establish a network connection between the two nodes.
3. The preflight stage begins. Check if the various resources available are compatible
between the source and destination nodes:
. Are the processors using similar architecture? (For example, a virtual machine
running on an AMD node cannot be moved to an Intel node, and vice versa.)
. Are there a sufficient number of CPU cores available on the destination?
. Is there sufficient RAM available on the destination?
. Is there sufficient access to required shared resources (VHD, network, and so on)?
. Is there sufficient access to physical device resources that must remain associ-
ated with the virtual machine after migration (CD drives, DVDs, and LUNs or
offline disks)?
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Deploying and Using Windows Virtualization
Migration cannot occur if there are any problems in the preflight stage. If there are,
the virtual machine will remain on the source node and processing ends here. If
preflight is successful, migration can occur and the virtual machine transfer continues.
4. The virtual machine state (inactive memory pages) moves to the target node to
reduce the active virtual machine footprint as much as possible. All that remains on
the source node is a small memory working set of the virtual machine.
The virtual machine configuration and device information are transferred to the
destination node and the worker process is created. Then, the virtual machine
memory is transferred to the destination while the virtual machine is still running.
The cluster service intercepts memory writes and tracks actions that occur during the
migration. This page will be retransmitted later. Up to this point, the virtual
machine technically remains on the source node.
5. What remains of the virtual machine is briefly paused on the source node. The virtu-
al machine working set is then transferred to the destination host, storage access is
moved to the destination host, and the virtual machine is reset on the destination
host.
The only downtime on the virtual machine occurs in the last step, and this outage is
usually much less than most network applications are designed to tolerate. For example,
an administrator can be accessing the virtual machine via Remote Desktop while it is
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being Live Migrated and will not experience an outage. Or a virtual machine could be
streaming video to multiple hosts, Live Migrated to another node, and the end users don’t
know the difference.
Use the following steps to perform a Live Migration between two cluster nodes:
1. On one of the cluster nodes, open Failover Cluster Management.
2. Expand the Cluster and select Services and Applications.
3. Select the virtual machine to Live Migrate.
4. Click Live Migrate Virtual Machine to Another Node in the Actions pane and select
the node to move the virtual machine to. The virtual machine will migrate to the
selected node using the process described previously.
NOTE
If there are processor differences between the source and destination node, Live
Migration will display a warning that the CPU capabilities do not match. To perform a
Live Migration, you must shut down the virtual machine and edit the settings of the
processor to “Migrate to a Physical Computer with a Different Processor Version”.
Microsoft Hyper-V has come a long way in just a few short years, and even further since
Windows Server 2008 was released. As recently as 2003, Microsoft wasn’t even in the
virtualization game, and now with Windows Server 2008 R2, virtualization provides orga-
Best Practices
1551
nizations with a way to consolidate server applications onto a fewer number of virtual
server systems and provide enterprise-level fault tolerance. Key to the release of Windows
Server 2008 R2 Hyper-V is the ability to perform Live Migrations, reducing failover times
from minutes to nearly instantaneous. This technology competes directly with other
competitors, such as VMware, head-to-head, but at a much lower cost.
Hyper-V in Windows Server 2008 R2 provides the ability of hosting Windows server,
Windows client, and non-Windows guest sessions with the ability of consolidating dozens
of physical servers into a single virtual server system. By adding additional virtual server
systems to an enterprise, an organization can drastically reduce the number of physical
servers it has, plus provide a method of implementing server redundancy, clustering, and
disaster recovery without the need to double the number of physical servers the organiza-
tion requires to provide better computing services to the organization.
The following are best practices from this chapter:
. Plan for the number of virtual guest sessions you plan to have on a server to prop-
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erly size the host system with respect to memory, processor, and disk requirements.
. Have the installation media and license keys needed for the installation of the
guest operating system handy when you are about to install the guest operating
system session.
. Apply all patches and updates on guest sessions soon after installing the guest oper-
37
ating system, just as you would for the installation of updates on physical systems.
. For Microsoft Windows guest sessions, install the Windows add-in components to
improve the use and operation of the guest session.
. After installing the guest session and its associated applications, confirm whether the
memory of the guest session is enough, and adjust the memory of the guest session
accordingly to optimize the performance of the guest session.
. Allocate enough disk space to perform snapshots of images so that the disk subsys-
tem can handle both the required guest image and the associated snapshots of the
guest session.
. Consider using snapshots before applying major patches, updates, or upgrades to an
image session to allow for a rollback to the original image.
. Consider Live Migration instead of Quick Migration to quickly migrate virtual
servers between hosts with little to zero downtime.
. Ensure that the hardware used in Live Migration is on the Windows Server 2008 R2
compatibility list and is using the same Intel or AMD platform.
. Use Cluster Shared Volumes only for Hyper-V Live Migration clusters.
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Deploying and Using Windows Virtualization
. Configure the Windows failover cluster before adding shared storage, which will be
provisioned as Cluster Shared Volumes.
. For Live Migration nodes, change the default location to store virtual machines to
the Cluster Shared Volume path.
. Ensure that both the virtual machine configuration file and its associated virtual hard
disk (VHD) files reside in the CSV folder location for Live Migration virtual machines.
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SYMBOLS
$Error
s variable, 741
A
accelerators
access-based enumeration, 1122,
1162
applications, troubleshooting
, 1282
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disaster recovery
, 1277-1282
files, auditing
, 431-433
Group Policy
, 585-586
groups,
RDS, 958
logon
smar
t cards, 423
networks, troubleshooting
, 1278
1554
access
OUs,
delegating administration, 184-186
Performance Options window
, 1418
activation
permissions,
471
RD Licensing server
s, 978
Windows Ser
ver Core, 108
Pow
erShell, 705
Active Directory. See AD
Registry
, 745
Active Directory Administrative Center
, 19
remote, 847-850. See also remote access
Active Directory Certificate Services. See AD CS
Active Directory Domain Services. See AD DS
resources, auditing
, 671-674
Active Directory Federation Services. See AD FS
Routing and Remote Access dialog box, 479
Active Directory in Application Mode (ADAM),
Active Directory Lightweight Directory Services.
Unmapped UNIX User Access, 247
See AD LDS
Windows Ser
ver Backup, 1285-1287
Active Directory Rights Management Services.
access-based enumeration,
1122-1123,
See AD RMS
Active Directory Users and Computer
s tool, 17
access control entries (A
CEs), 178
active nodes,
1179
Access Per
mission section, 479
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active/active clusters,
1180
accidental deletion protection, 1254-1255
active/passive cluster
s, 1179
accounting impro
vements in NPS, 461
ActivePer
l scripts, 257
accounts
activity logs,
DHCP access, 350
activity, monitoring user
s, 1349
disaster recover
y documentation, 1234
AD (Active Directory)
FIM, provisioning
, 238,
241-243
Group Account Migration Wizard, 511
Certificate Services,
1257-1259
preformatting AD computer
, 1013
RMS Service,
453
clients,
monitoring configuration, 823-824
security
, 814
computer accounts, preformatting
, 1013
Ser
vice Account Migration Wizard, 515
containers, delegating GPO administrative
A
CEs (access control entries), 178
DNS zones
moving
, 505
tasks,
1386
Federation Services,
expansion in, 21
AD DS (Active Directory Domain Services)