Module 13: Network Load Balancing Fundamentals

Server Availability and Scalability Overview Windows Network Load Balancing Configuring Windows Network Load Balancing

Lesson 1: Server Availability and Scalability Overview What Is Availability? What Is Scalability? What Is Load Balancing? Comparing Hardware and Software Load Balancing What Is Failover Clustering?

What Is Availability? Availability is a level of service that applications, services, or systems provide, expressed as a percentage of time Highly available services or systems are available more than 99% of the time Availability is a level of service that applications, services, or systems provide, expressed as a percentage of time Highly available services or systems are available more than 99% of the time High availability: Requirements differ based on how availability is measured Does not typically include planned outages when calculating availability

What Is Scalability? Scalability measures the ability to increase capacity Scaling up: Increases the capacity of a single server Involves adding more or better hardware to a server Scaling out: Increases the capacity of an application Involves adding additional servers to perform processing

What Is Load Balancing? Load Balancing is a system that increases the scalability and availability of the servers that provide access to data Other load balancing methods: A virtual IP address is used to distribute requests between multiple servers Not suitable for all applications

Comparing Hardware and Software Load Balancing Hardware load balancing: Uses a device to provide the virtual IP Requires multiple devices to guarantee fault tolerance Software load balancing: All cluster nodes provide the virtual IP There is no single point of failure

What Is Failover Clustering? Passive Node Active Node Shared Storage Shared Storage Private Network Public Network

Lesson 2: Windows Network Load Balancing What Is Windows Network Load Balancing? Requirements for Windows Network Load Balancing How Windows Network Load Balancing Works Data Synchronization between NLB Nodes

What Is Windows Network Load Balancing? Windows NLB: Is a fully distributed software solution for load balancing Is included with all versions of Windows Server® 2008 Session Broker: For Terminal Services Distributes session requests to the least loaded server Provides scalability and availability Included in all version of Windows Server 2008

Requirements for Windows Network Load Balancing Requirements: At least one network adapter for load balancing Only TCP/IP on the NLB adapter All NLB nodes on the same subnet

How Windows Network Load Balancing Works Unicast mode: A unique NLB MAC address is assigned to NLB adapter in all nodes The original MAC address of the NLB adapter cannot be used Packets are received by all NLB nodes Only the appropriate NLB node responds Outgoing MAC is unique for each node to avoid switch problems Multicast mode: A multicast MAC address is assigned to the NLB adapter in all nodes The original MAC address of the NLB adapter can still be used Removes the need for two network adapters Only the appropriate NLB node responds

Data Synchronization between NLB Nodes All NLB nodes must have the same data to make sure that all nodes respond identically to requests Data access can be provided by: Synchronizing content between servers Storing data in a common location NLB Cluster Database Server

Lesson 3: Configuring Windows Network Load Balancing What Are the Cluster Parameters? What Are Port Rules? What Is the Filtering Mode? What Is Affinity? What Are the Host Parameters? Demonstration: Creating an NLB Cluster

What Are the Cluster Parameters? Cluster parameterDescription IP addressVirtual IP address of the NLB cluster Network addressMAC address of the NLB cluster Cluster operation mode Specified whether unicast or multicast operation is used Cluster parameters include the following:

What Are Port Rules? Port rules specify how requests to a certain IP address and port range are handled Port rules define: Filtering mode Affinity Load weight Handling priority

What Is the Filtering Mode? Filtering modeDescription Multiple hosts All NLB nodes respond based on the weight assigned to each node Single host Only the NLB node with the highest priority responds Disable this port rangeAll traffic for this port range is blocked

What Is Affinity? AffinityDescription None Each client request could be distributed to any node Single All requests from a single client are distributed to a single node Network All requests from a single class C sized network are distributed to a single node Affinity controls how requests from a client are distributed among multiple nodes in an NLB cluster

What Are the Host Parameters? Host parameterDescription Initial host state Specifies whether the host automatically joins the NLB cluster when started Dedicated IP address IP address that is used on the host for cluster management Priority Determines in which order the host is when a port rule does not apply Host parameters include the following:

Demonstration: Creating an NLB Cluster In this demonstration, you will see how to configure an NLB cluster

Lab: Implementing Network Load Balancing Exercise 1: Preparing Web Servers for NLB Exercise 2: Creating an NLB Cluster for Failover Exercise 3: Configuring an NLB Cluster for Load Balancing Logon information Virtual machine NYC-DC1, NYC-WEB, NYC-SVR1 User name Administrator Password Pa$$w0rd Estimated time: 60 minutes

Lab Review When an NLB cluster is configured with single host filtering mode, how is the responding node determined? When an NLB cluster is configured with multihost filtering mode, how is the responding node determined?

Module Review and Takeaways Review Questions Real-world Issues and Scenarios Best Practices Tools