The NLB feature in win server 2008 enhances the ability and scalability of Internet applications such as those used on web, ftp, vpn and other mission critical servers. When a host has failed, ihe remaining hosts in the cluster converge and ensure that all new client requests are handled by surviving hosts. However, if u bring a host down intentionally can use the “wlbs drainstop” command to service all active connections prior to bringing the computer offline. When it is ready, the offline computer can transiently re-join the cluster and regain its share of workload, which allow the other computers in the cluster to handle less traffic.
Note that NLB supports up to 32 computers in a single cluster.
Lab configuration:
Server1 10.10.10.20 Nlb1.sign.com
Server2 10.10.10.21 Nlb2.sign.com
Virtual cluster 10.10.10.22 Cluster.sign.com
Step1: Install web-server role and configure a website.
Step2: Install NLB role on both server1 and server2 machines.
Step3: Log on to server1 with sufficient privileges, go to start> admin tool> NLB manager> select cluster menu> select new.
Step4: Add host name and click connect.
Step6: On next page select priority 1 and default state started.
Step6: On next page Add cluster IP address.
Step7: On next cluster parameter page add cluster name and select “Unicast” as cluster operational mode.
If you select multicast support, NLB converts the cluster MAC address that belongs to the cluster adapter into a multicast address. It also ensures that the cluster’s primary IP address resolves to this multicast address as part of the ARP protocol. The adapter can now use its original, built-in MAC address that was disabled in unicast mode. In multicast mode, you can also enable Internet Group Management Protocol (IGMP) support, which limits switch flooding by limiting traffic to Network Load Balancing ports only. That is, enabling IGMP support ensures that traffic intended for an NLB cluster passes through only those ports that are serving the cluster hosts and not all switch ports.
If you select unicast support, NLB automatically instructs the driver that belongs to the cluster adapter to override the adapter’s unique, built-in network address and to change its MAC address to the cluster’s MAC address. This is the address used on all cluster hosts. You do not need to manually configure the network adapter to recognize this address. (Note that some network adapters do not support changing their MAC addresses. If you experience this issue, you must install a network adapter that does.)
Step8: On next page either configure port rule or leave default as your need.
Step9: Now your cluster node1 is online.
Step10: Log on to Node2 with sufficient privileges, go to start> Admin tool> NLB manager> click on cluster menu> click on connect to existing.
Step11: After openings connect page add previous host name of cluster and click connect.
Step12: after connecting to a cluster, right click on cluster name and select add host to cluster.
Step13: After opening connect page Add second host name and click connect.
Step14: On next page select priority 2 and default state started.
Dtep15: On port rule page leave this default.
Step16:Now your NLB server Is ready to server……….
Step 17: you can configure load weight by selecting nlb1>host menu> properties> port rules> edit> under filtering mode.
Filtering mode, configure the following parameters:
The Multiple hosts parameter specifies that multiple hosts in the cluster will handle network traffic for the associated port rule. This filtering mode provides scaled performance and fault tolerance by distributing the network load among multiple hosts. You can specify that the load be equally distributed among the hosts or that each host will handle a specified load weight.
The Single host parameter specifies that network traffic for the associated port rule be handled by a single host in the cluster according to the specified handling priority. This filtering mode provides port specific fault tolerance for handling network traffic.
The Disable this port range parameter specifies that all network traffic for the associated port rule be blocked. In this case, the NLB driver filters all corresponding network packets or datagrams. This filtering mode lets you block network traffic that is addressed to a specific range of ports.
The Affinity parameter is applicable only for the multiple hosts filtering mode.
The None option specifies that multiple connections from the same client IP address can be handled by different cluster hosts (there is no client affinity). To allow Network Load Balancing to properly handle IP fragments, you should avoid using None when selecting UDP or Both for your protocol setting.
The Single option specifies that NLB should direct multiple requests from the same client IP address to the same cluster host. This is the default setting for affinity. You can optionally modify the NLB client affinity to direct all client requests from a TCP/IP Class C address range (instead of a single IP address) to a single cluster host by enabling the Network option instead of the Single option. This feature ensures that clients that use multiple proxy servers to access the cluster can have their TCP connections directed to the same cluster host.
The Load weight parameter is applicable only for the Multiple hosts filtering mode. You can configure this parameter only when you open the port rules dialog box through Host Properties. (This parameter is not configurable when you open the port rules dialog box through Cluster Properties.)
When using the Multiple hosts filtering mode, this parameter specifies the relative amount of load-balanced network traffic that this host should handle for the associated port rule. Allowed values range from 0 (zero) to 100. To prevent a host from handling any network traffic, set the load weight to 0 (zero). The actual fraction of traffic handled by each host is computed as the local load weight divided by the sum of all load weights across the cluster.
You can specify different load weights for each host in the cluster by using the Load weight parameter. You can specify that all hosts distribute the network load equally by using the Equal load distribution parameter instead of the Load weight parameter.
Test cluster Configuration:
Step17: Go to the command prompt and type “wlbs query”, as you can see node 1 and node 2 converged successfully on the cluster. This means things are working well.
• Ping each server locally and remotely
• Ping the virtual IP locally and remotely – you should do this three times from each location. If you cannot ping remotely you may need to add a static ARP entry in your switches and/or routers where the host machines reside.
Step18: You can see a LAN property is configured with a virtual IP 10.10.10.22.
Step19: Now Access your clustered website.
All reasults those are mentioned above shows your cluster is operating fine……………
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