Read Windows Server 2008 R2 Unleashed Online
Authors: Noel Morimoto
template. Actual guest session resources are not permanently allocated but rather allocated
and dedicated at the time of logon.
VDI is covered in more detail in Chapter 25.
Improvements in Clustering and Storage Area Network Support
37
Improvements in Clustering and Storage Area
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Although clustering of servers has been around for a long time in Windows (dating back
to Windows NT 4.0, when it was available, but really didn’t work), clustering in Windows
Server 2008 R2 now not only works, but also provides a series of significant improvements
that actually make clustering work a whole lot better.
As IT administrators are tasked with the responsibility of keeping the network operational
24 hours a day, 7 days a week, it becomes even more important that clustering works.
Fortunately, the cost of hardware that supports clustering has gotten significantly less
expensive; in fact, any server that meets the required specifications to run Windows Server
2008 R2, Enterprise Edition can typically support Windows clustering. The basic standard
for a server that is used for enterprise networking has the technologies built in to the
system for high availability. Windows Server 2008 R2, Enterprise Edition or Datacenter
Edition is required to run Windows Server 2008 R2 clustering services.
Clustering is covered in detail in Chapter 29, “System-Level Fault Tolerance
(Clustering/Network Load Balancing).”
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No Single Point of Failure in Clustering
Clustering by definition should provide redundancy and high availability of server
systems; however, in previous versions of Windows clustering, a “quorum drive” was
required for the cluster systems to connect to as the point of validation for cluster opera-
tions. If at any point the quorum drive failed, the cluster would not be able to failover
from one system to another. Windows Server 2008 and Windows Server 2008 R2 cluster-
ing removed this requirement of a static quorum drive. Two major technologies facilitate
this elimination of a single or central point of failure, which include majority-based
cluster membership verification and witness-based quorum validation.
The majority-based cluster membership enables the IT administrator to define what
devices in the cluster get a vote to determine whether a cluster node is in a failed state
and the cluster needs to failover to another node. Rather than assuming that the disk will
always be available as in the previous quorum disk model, now nodes of the cluster and
shared storage devices participate in the new enhanced quorum model in Windows
Server 2008 R2. Effectively, Windows Server 2008 R2 server clusters have better informa-
tion to determine whether it is appropriate to failover a cluster in the event of a system
or device failure.
The witness-based quorum eliminates the single quorum disk from the cluster operation
validation model. Instead, a completely separate node or file share can be set as the file
share witness. In the case of a GeoCluster where cluster nodes are in completely different
locations, the ability to place the file share in a third site and even enable that file share
to serve as the witness for multiple clusters becomes a benefit for both organizations with
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distributed data centers and also provides more resiliency in the cluster operations
components.
Stretched Clusters
Windows Server 2008 R2 also introduced the concept of stretched clusters to provide
better server and site server redundancy. Effectively, Microsoft has eliminated the need to
have cluster servers remain on the same subnet, as has been the case in Windows cluster-
ing in the past. Although organizations have used virtual local area networks (VLANs) to
stretch a subnet across multiple locations, this was not always easy to do and, in many
cases, technologically not the right thing to do in IP networking design.
By allowing cluster nodes to reside on different subnets, plus with the addition of a
configurable heartbeat timeout, clusters can now be set up in ways that match an organi-
zation’s disaster failover and recovery strategy.
Improved Support for Storage Area Networks
Windows Server 2008 R2 also has improved its support for storage area networks (SANs)
by providing enhanced mechanisms for connecting to SANs as well as switching between
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SAN nodes. In the past, a connection to a SAN was a static connection, meaning that a
server was connected to a SAN just as if the server was physically connected to a direct
attached storage system. However, the concept of a SAN is that if a SAN fails, the server
should reconnect to a SAN device that is now online. This could not be easily done with
Windows 2003 or prior. SCSI bus resets were required to disconnect a server from one SAN
device to another.
With Windows Server 2008 R2, a server can be associated with a SAN with a persistent reser-
vation to access a specific shared disk; however, in the event that the SAN fails, the server
session can be logically connected to another SAN target system without having to script
device resets that have been complicated and disruptive in disaster recovery scenarios.
Beyond the standard migration tools that help administrators migrate from one version of
Active Directory to another, or to perform an in-place upgrade from one version of
Windows to another, Windows Server 2008 R2 has migration tools to help administrators
move entire server roles from one system to another. These new tools provide migration
paths from physical servers to virtual servers, or from virtual servers to physical servers.
Other tools allow for the migration of DHCP configuration and lease information from
one server to another. These tools and the prescriptive guidance help administrators
migrate servers more easily than ever before.
Addition of Migration Tools
39
Operating System Migration Tools
Windows Server 2008 R2 provides tools that help administrators migrate from older
1
versions of the Windows Server operating system to Windows Server 2008 R2. The
supported migration paths are as follows:
.
Windows Server 2003, Windows Server 2003 R2, Windows Server 2008, and
Windows Server 2008 R2—
These operating systems can be migrated to Windows
Server 2008 R2 using the operating system migration tools and guidance documenta-
tion.
.
x86 and x64—
Servers can be migrated from x86 to x64 and from x64 to x64 with
limitations. Because Windows Server 2008 R2 is an x64 operating system only, there
is no in-place upgrade support from x86 to x64, so the upgrade path is a server-to-
server transition, not in-place. However, x64 to x64 in-place is supported as long as
any applications sitting on the server can be upgraded from one x64 platform to the
Windows Server 2008 R2 x64 platform.
.
Full Server and ServerCore—
Operating system migration from Full Server to
ServerCore and from ServerCore to Full Server are supported typically as a server-to-
server migration because in-place migrations between Full Server and ServerCore
have limitations. The GUI needs to be added or removed and, thus, applications are
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typically migrated rather than complete operating system migrations between the
platforms.
.
Physical and virtual—
Virtualization of guest sessions is the de facto standard in
data centers these days and the implementation of applications on virtual guest ses-
sions is the norm. As such, organizations wanting to migrate from physical server
configurations to virtual guest sessions can leverage the migration tools and guid-
ance available in performing server and application migrations to virtual server roles.
Server Role Migrations
Included in Windows Server 2008 R2 are tools and guidance that help administrators
migrate server roles to Windows Server 2008 R2 server systems. The supported migration
paths are as follows:
.
Active Directory Domain Services—
The migration from Active Directory 2003
and Active Directory 2008 to Active Directory 2008 R2 is fully supported and
covered in Chapter 16 of this book.
.
DNS and DHCP migrations—
New migration tools are available that help adminis-
trators migrate their DNS and DHCP servers from running on previous versions of
Windows to servers running Windows Server 2008 R2, and not only just the service
configurations but also DNS and DHCP data. In the past, the migration of DHCP to
a new server usually meant the loss of DHCP lease information. With the new
migration tools in Windows Server 2008 R2, an administrator can now migrate the
server configuration as well as the lease data, including lease expiration data, as part
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Windows Server 2008 R2 Technology Primer
of the migration process. These migration tools are covered in Chapters 10 and 11
of this book.
.
File and print migrations—
Included in the migration tools for Windows Server
2008 R2 are features that migrate file data, included file permissions, and the migra-
tion of print server configurations and settings from older servers to new Windows
Server 2008 R2 configurations. These migration tools help simplify the process of
updating servers from old server systems to new systems with the least amount of
impact on the organization and drastically simplify the process of migration for
domain administrators.
Improvements in Server Roles in Windows Server
The introduction of Windows Server 2008 R2 added new server roles to Windows as well
as enhanced existing roles based on feedback Microsoft received from organizations on
features and function wish lists. Server roles are no longer installed by default on a
Windows Server 2008 R2 server and have to be selected for installation after the initial
installation of the Windows operating system.
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Some of the new or improved server roles in Windows Server 2008 R2 include Internet
Information Services 7.5, SharePoint Services, Rights Management Service, and Windows
virtualization.
Introducing Internet Information Services 7.5
Internet Information Services 7.5 (IIS) is the seventh-generation web server service from
Microsoft. Microsoft completely redesigned IIS 7.0 in Windows Server 2008 rather than
just adding more functions and capabilities to the exact same IIS infrastructure as they
have done for the past several years. The good part of the new IIS 7.x is that it now
provides organizations with the ability to manage multiple web servers from a single
console, rather than having to install components and configure each web server individ-
ually. This requires organizations to rethink and redesign their web management tasks
from pushing the same content to dozens of servers individually to a process where infor-
mation is pushed to a Shared Configuration store, where common information is posted
and shared across all IIS 7.x servers. Organizations can continue to post information the
old way by pushing information individually to each server; however, to gain the advan-
tage of the new IIS 7.x services, redesigning how information gets posted should be
changed to meet the new model.
The advantage of the new model of content posting is that information is stored, edited,
and managed in a single location. At a designated time, the information in the single loca-
tion is posted to each of the servers in the shared application hosting farm. This is a signif-
icant improvement for organizations managing and administering a lot of IIS web servers.
This ensures that all servers in a farm are using the same content, have been updated
simultaneously, and any changes are ensured to be propagated to the servers in the farm.
Web administrators no longer have to worry that they forgot a server to update, or to
Improvements in Server Roles in Windows Server 2008 R2
41
stage an update at a time when each individual server could be updated in a fast enough
sequence that the experience of all users was going to occur at around the same time.
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IIS 7.5 is covered in detail in Chapter 12, “Internet Information Services.”
Windows SharePoint Services
A significant update provided as part of the Windows Server 2008 client access license
(CAL) is the ability to load and run Windows SharePoint Services. Now in its third genera-
tion, Windows SharePoint Services (WSS) is a document-storage management application
that provides organizations with the capability to better manage, organize, and share
documents, as well as provide teams of users the ability to collaborate on information.
Windows SharePoint Services sets the framework from which the Microsoft Office
SharePoint Services 2007 (MOSS) is built. MOSS leverages the core functionality of WSS
and extends the capability into enterprise environments. WSS is the basis of document
sharing and communications for organizations in the evolution of file and information