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Chapter 6
SERVER CLUSTERING
Chapter 6: SERVER CLUSTERING
OVERVIEW
 List the types of server clusters.
 Determine which type of cluster to use for your
applications.
 Describe how Network Load Balancing and server
clusters work.
 Deploy an NLB cluster.
 Deploy a server cluster.
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Chapter 6: SERVER CLUSTERING
WINDOWS SERVER 2003 CLUSTER TYPES
 Server clusters
 Network Load Balancing clusters
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SERVER CLUSTERS
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Chapter 6: SERVER CLUSTERING
NETWORK LOAD BALANCING
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Chapter 6: SERVER CLUSTERING
DESIGNING A CLUSTERING SOLUTION
 What are you protecting against?
 Software failure
 Hardware failure
 Site failure
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ESTIMATING AVAILABILITY REQUIREMENTS
 Decide what applications are required, and how
much downtime can be tolerated.
 Consider what threats may be present—they will not
be the same in every situation or environment.
 Investment in fault tolerance and availability is
governed by the laws of diminishing returns.
Spending twice as much will not provide double the
protection.
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SCALING CLUSTERS
Scale up
 Improve performance of systems by installing a
more powerful processor and adding RAM and
higher performance disk subsystems.
Scale out
 Add servers to cluster to increase overall processing
power.
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HOW MANY CLUSTERS?
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COMBINING CLUSTERING TECHNOLOGIES
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DISPERSING CLUSTERS
 Geographic separation provides higher availability in
situations such as:
 Natural disaster (flood, earthquake, tornado)
 Power failure, rolling blackouts
 Theft, vandalism, terrorism
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USING NETWORK LOAD BALANCING
 Easier to install, configure, and maintain than server
clustering.
 Does not require additional storage hardware.
 No additional software is required.
 Managed via the Network Load Balancing Manager
application.
Chapter 6: SERVER CLUSTERING
UNDERSTANDING NETWORK LOAD
BALANCING
 Each NLB cluster can consist of up to 32 servers.
 A virtual network adapter acts as an intermediary
between the physical network interface and the
protocol stack.
 An algorithm associated with the virtual network
adapter determines which requests should be
answered and which should be ignored.
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Chapter 6: SERVER CLUSTERING
PLANNING A NETWORK LOAD BALANCING
DEPLOYMENT
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Chapter 6: SERVER CLUSTERING
NLB OPERATIONAL MODES
Unicast mode
 Servers in the cluster can only communicate with
each other if more than one network interface is
installed in the server.
Multicast mode
 Servers with one network card can communicate
with each other, but any routers on the network
must support multicast MAC addresses.
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NLB NETWORKING
 Servers in an NLB cluster determine independently
whether or not to process an incoming request.
 Servers in an NLB cluster transmit heartbeat
messages to let the other servers in the cluster
know they are running and operational.
 Heartbeats are the only cluster-related
communication between servers in an NLB cluster.
Chapter 6: SERVER CLUSTERING
DEPLOYING A NETWORK LOAD BALANCING
CLUSTER
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MONITORING NETWORK LOAD BALANCING
 Monitoring of NLB clusters can be performed using:
 Network Load Balancing Manager
 Event Viewer
Chapter 6: SERVER CLUSTERING
USING NETWORK LOAD BALANCING
MANAGER
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USING EVENT VIEWER
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USING NLB.EXE
 Command line utility used to configure and manage
NLB clusters
 Enables commands to be placed into scripts and
batch files
Chapter 6: SERVER CLUSTERING
DESIGNING A SERVER CLUSTER
 Designing a server cluster deployment
 Planning a server cluster hardware configuration
 Creating an application deployment plan
 Selecting a quorum model
 Creating a server cluster
 Configuring failover policies
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DESIGNING A SERVER CLUSTER DEPLOYMENT
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PLANNING A SERVER CLUSTER HARDWARE
CONFIGURATION
 All servers in the cluster must be running the same
edition of Windows Server 2003.
 All servers in the cluster must have the same
processor architecture: 32-bit or 64-bit.
 At least one network interface per system is
required. Two are preferred.
 Shared storage connection is required.
Chapter 6: SERVER CLUSTERING
USING SCSI
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USING FIBRE CHANNEL
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CREATING AN APPLICATION DEPLOYMENT
PLAN
Single-instance applications
 Applications that can run on no more than one
server at a time, using a given configuration
Multiple-instance applications
 Applications in which duplicated code can run on
multiple nodes in a cluster or in which the code can
be partitioned
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DEPLOYING SINGLE-INSTANCE APPLICATIONS
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CAPACITY PLANNING
 Idle servers in a standby configuration must be
capable of running the application(s) on the active
server.
 Depending on the failover configuration, the idle
server may be required to run more than one
application in the event of a multiple server failure.
Chapter 6: SERVER CLUSTERING
DEPLOYING MULTIPLE-INSTANCE
APPLICATIONS
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Chapter 6: SERVER CLUSTERING
SELECTING A QUORUM MODEL
 Single-node cluster
 Single-quorum device cluster
 Majority node set cluster
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CREATING A SERVER CLUSTER
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CONFIGURING FAILOVER POLICIES
 Failover pairs
 Hot-standby server
 N+I
 Failover ring
 Random
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CHAPTER SUMMARY
 A cluster is a group of servers that appears to users
as a single resource and that provides high
availability, reliability, and scalability for specific
applications.
 A Network Load Balancing cluster is a group of
servers running a stateless application, such as a
Web server, each of which has an identical,
independent data store.
 A server cluster is a group of servers running a
stateful application, such as a database server, and
sharing a common data store.
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CHAPTER SUMMARY (continued)
 Network Load Balancing works by creating a virtual
network adapter with IP and MAC addresses that
represent the cluster as a single unit.
 When NLB is running in unicast mode, ordinary
communication between cluster servers is
impossible. In multicast mode, the cluster servers
can communicate normally.
 Although NLB and server clusters can both function
with a single network interface adapter installed in
each server, using multiple adapters in each server
can prevent network performance degradation.
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CHAPTER SUMMARY (continued)
 A server cluster requires a storage resource shared
by the nodes in the cluster. Windows Server 2003
supports shared SCSI and Fibre Channel for this
purpose.
 In a server cluster, the quorum is a storage resource
that contains cluster configuration data, which
nodes use to create their configuration databases
as they join the cluster.
 You can configure a cluster to use various failover
policies by specifying which nodes are permitted to
run various cluster resources.
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CHAPTER SUMMARY (continued)
 To create and manage server clusters, use the
Cluster Administrator application. To manage
Network Load Balancing clusters, use Network Load
Balancing Manager.