11 SERVER CLUSTERING Chapter 6

Chapter 6: SERVER CLUSTERING2 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.  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.

Chapter 6: SERVER CLUSTERING3 WINDOWS SERVER 2003 CLUSTER TYPES  Server clusters  Network Load Balancing clusters  Server clusters  Network Load Balancing clusters

Chapter 6: SERVER CLUSTERING4 SERVER CLUSTERS

Chapter 6: SERVER CLUSTERING5 NETWORK LOAD BALANCING

Chapter 6: SERVER CLUSTERING6 DESIGNING A CLUSTERING SOLUTION  What are you protecting against?  Software failure  Hardware failure  Site failure  What are you protecting against?  Software failure  Hardware failure  Site failure

Chapter 6: SERVER CLUSTERING7 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.  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.

Chapter 6: SERVER CLUSTERING8 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. 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.

Chapter 6: SERVER CLUSTERING9 HOW MANY CLUSTERS?

Chapter 6: SERVER CLUSTERING10 COMBINING CLUSTERING TECHNOLOGIES

Chapter 6: SERVER CLUSTERING11 DISPERSING CLUSTERS  Geographic separation provides higher availability in situations such as:  Natural disaster (flood, earthquake, tornado)  Power failure, rolling blackouts  Theft, vandalism, terrorism  Geographic separation provides higher availability in situations such as:  Natural disaster (flood, earthquake, tornado)  Power failure, rolling blackouts  Theft, vandalism, terrorism

Chapter 6: SERVER CLUSTERING12 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.  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 CLUSTERING13 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.  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.

Chapter 6: SERVER CLUSTERING14 PLANNING A NETWORK LOAD BALANCING DEPLOYMENT

Chapter 6: SERVER CLUSTERING15 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. 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.

Chapter 6: SERVER CLUSTERING16 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.  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 CLUSTERING17 DEPLOYING A NETWORK LOAD BALANCING CLUSTER

Chapter 6: SERVER CLUSTERING18 MONITORING NETWORK LOAD BALANCING  Monitoring of NLB clusters can be performed using:  Network Load Balancing Manager  Event Viewer  Monitoring of NLB clusters can be performed using:  Network Load Balancing Manager  Event Viewer

Chapter 6: SERVER CLUSTERING19 USING NETWORK LOAD BALANCING MANAGER

Chapter 6: SERVER CLUSTERING20 USING EVENT VIEWER

Chapter 6: SERVER CLUSTERING21 USING NLB.EXE  Command line utility used to configure and manage NLB clusters  Enables commands to be placed into scripts and batch files  Command line utility used to configure and manage NLB clusters  Enables commands to be placed into scripts and batch files

Chapter 6: SERVER CLUSTERING22 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  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

Chapter 6: SERVER CLUSTERING23 DESIGNING A SERVER CLUSTER DEPLOYMENT

Chapter 6: SERVER CLUSTERING24 PLANNING A SERVER CLUSTER HARDWARE CONFIGURATION  All servers in the cluster must be running the same edition of Windows Server  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.  All servers in the cluster must be running the same edition of Windows Server  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 CLUSTERING25 USING SCSI

Chapter 6: SERVER CLUSTERING26 USING FIBRE CHANNEL

Chapter 6: SERVER CLUSTERING27 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 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

Chapter 6: SERVER CLUSTERING28 DEPLOYING SINGLE-INSTANCE APPLICATIONS

Chapter 6: SERVER CLUSTERING29 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.  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 CLUSTERING30 DEPLOYING MULTIPLE-INSTANCE APPLICATIONS

Chapter 6: SERVER CLUSTERING31 SELECTING A QUORUM MODEL  Single-node cluster  Single-quorum device cluster  Majority node set cluster  Single-node cluster  Single-quorum device cluster  Majority node set cluster

Chapter 6: SERVER CLUSTERING32 CREATING A SERVER CLUSTER

Chapter 6: SERVER CLUSTERING33 CONFIGURING FAILOVER POLICIES  Failover pairs  Hot-standby server  N+I  Failover ring  Random  Failover pairs  Hot-standby server  N+I  Failover ring  Random

Chapter 6: SERVER CLUSTERING34 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.  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.

Chapter 6: SERVER CLUSTERING35 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.  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.

Chapter 6: SERVER CLUSTERING36 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.  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.

Chapter 6: SERVER CLUSTERING37 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.