Filtering Mode

By configuring the Filtering mode, you can choose how to distribute the network traffic for the port rule among your NLB cluster hosts. You have two major choices Multiple host or single host, as well as a third choice that won't be used often Disable this port range. Multiple Host Selecting Multiple Host option specifies that multiple hosts in the NLB cluster can handle the network traffic associated with the specific port rule. Many advantages exist to using the Multiple Host option, such as...

Event ID

Source Service Control Manager Description Logon attempt with current password failed with the following error There are currently no logon servers available to service the logon request. More Info The description for this error message might vary somewhat based on the actual error. For example, another error that could be listed in the event detail might be Logon Failure unknown username or bad password. Problem The service control manager attempted to start a service. It couldn't...

Client Affinity None Single and Class C

Affinity, the natural drawing of services to one node over another, is set by selecting Single, Class C, or None. Affinity settings exist because, in today's web culture, business is done over the Internet with millions of customers coming to your web sites (or better yet, e-commerce sites) to shop and do business with you. A shopper enters a credit card number or wants to make a transaction with your web server. The hope is that you're using highly available architecture. If not, what happens...

Active Passive

Active Passive is defined as a cluster group where one server is handling the entire load and, in case of failure and disaster, a Passive node is standing by waiting for failover (as seen in Figure 1-9). This is commonly used, but most would argue that you're still wasting the resources of that server standing by. Wouldn't it be helpful if they were both somehow working to serve the clients needed data and still have the benefits of failover That's what Windows 2000 clustering services can...

Using the NLB Command

After you enable Network Load Balancing on an adapter, you'll find a new executable file, nlb.exe, has appeared in your systemroot system32 folder. The nlb.exe command replaces the wlbs.exe command previously used in Windows NT 4.0 and Windows 2000 Server. The context for the NLB.exe command is nlb < command> < remote options> Table 3-6 lists the commands available for use with the nlb.exe command. Table 3-6 lists the commands available for use with the nlb.exe command. Displays the...

Clustering Services Installation

You've finally reached the point where you can install the Cluster Service. Although it seems we went through a ridiculous amount of work and effort to get here, you should now feel confident that you'll be building a nice house on a solid foundation. 1. First, open the Control Panel to view the applets. You'll find the Add Remove Programs applet within. As seen in Figure 2-10, you have an option in the bottom left-hand side of the dialog box to install Windows-based services that come with the...

NLB Security Design

In this section, you look at implementing security on your NLB solution. Because, for the most part, NLB clusters are exposed on the Internet, you might want to consider the following areas of this section to implement some security in your cluster. You aren't immune to attack. And you're in denial if you think your site won't be attacked or probed at least once by someone who's either curious or malicious in nature. The more important your site, the more you could find attacks coming your way....

NLB Traffic Planning

While using NLB, you want to ensure your data isn't bottlenecking anywhere because, as we've mentioned previously, it's critical for you to optimize every part of a Highly Available solution for it to work as advertised. You want it to operate faster, if anything else. You also want to make sure the Highly Available solution is scalable and redundant, but you definitely want to be certain your bandwidth needs are considered first. In the following diagram, I'll highlight a possible network...

Advanced Performance Monitoring Techniques

Monitoring use, processes, services, and events is also critical in performance management, baselining, and disaster recovery of any solution, especially one that's highly available. Your responsibility is to make certain your systems are running. Using a tool like this is a quick way to monitor the performance of several things, which are discussed next. Let's look at the Task Manager in detail. A Process Manager has existed in every incarnation of Windows in some form or another. The actual...

Configuring DHCP for High Availability

Now that you're familiar with the fundamentals of DHCP and why it should be included in your high-availability design, let's begin the steps on how to configure it. First, you need to review Chapter 2 and Chapter 3, where you learned how to cluster Microsoft Windows 2000 Advanced Server and Windows Server 2003. You need to work with an already clustered solution, so if you need to rebuild it, now is the time. If not, then you can apply this configuration later after you've read through it....

Load Balancing System Requirements

As you might suspect, before you can even get into setting up Windows Server 2003 NLB, you must first have met the hardware requirements to run Windows Server 2003. These requirements were outlined previously in Table 3-3. I recommend you go back and review the table again quickly before proceeding. Once you know what hardware requirements you must meet, you can safely begin the process of shopping for hardware to build your NLB solution. The best (and safest) way to do this is by working with...

Configuring the Performance Console

You can do some customization directly on the System Monitor. Before we add counters, let's look at the basic configuration of the monitor itself. In Figure 8-5, you can find the System Monitor Properties dialog box. Unfortunately, getting to this dialog box is only through the toolbar, so you need to look at the toolbar mentioned in the last section. Select the Properties icon, which is fourth from the last on the right. Click this icon, and you open the Properties Sheet. Once opened, you can...

Highly Available DHCP Services

DHCP is a service that, when installed and configured correctly, will take a massive administration burden off any network administrator or engineer. DHCP works with the assignment of IP addresses on your network. In other words, when you want your network clients to communicate with any device on the network, they need to speak the same protocol and be assigned with a unique logical address. This address (called an IP address) allows for this. The problem associated with this assignment...

MAC Source Configuration

If you set the settings to unicast, you can mask the Source MAC address. Masking the cluster MAC Address forces the NLB cluster nodes to use a dummy MAC address while they send data requests through the switch. The way this works is by tricking the switch into mapping the fake MAC to a port, while sending the frame to all ports on the switch to which they're destined to go. When configuring this workaround in Unicast mode, open the Registry Editor (Regedit.exe) and navigate to the following...

Designing Applications and Proper Bandwidth

What will you be running on this cluster This is going to bring you back to planning your hardware solution appropriately. In each of the following chapters, you'll be given a set of basic requirements, which you'll need to get your job done with the solution you're implementing. Of course, when you add services on top of the cluster itself, you'll also need to consider adding resources to the hardware. You should also consider the bandwidth connections based on the application. Bandwidth and...

Port Rules Port Range and Protocols

To configure Port Rules, you need to click the Port Rule tab within the Network Load Balancing Properties sheet. You'll automatically recognize the port range explained in the previous section. You can configure all ports for both Transport Layer protocols UDP and TCP. You can duplicate ports if they're for the same protocol. Using a different transport protocol, such as TCP or UDP, for instance, DNS will use port 53 for both TCP and UDP, but Zone Transfer will only go over the TCP 53 port. The...

Stateless vs Stateful Clustering

Windows 2000 clustering functions as stateful, which means the application state and user state are managed during and through the failover. This is an important design question to ask yourself in the early stages of planning the High Availability solution. Do you want stateful failover Most would answer yes, so application state isn't lost. That can be equated as what you were doing in time of failure. A stateless solution is one provided by network and component load balancing, where the...

Building a Load Balanced Cluster with Server

In this section, you work off the cluster solution you built in Chapter 3 and get into more advanced details. In Chapter 3, you built a load-balanced cluster with Windows Server 2003. The next steps you take build from that previous installation and configuration. I repeat a few of the main concepts from Chapter 3 but, if you haven't read Chapter 3, I suggest you do so before continuing. Let's begin. 1. You need to have at least two servers to configure a load-balanced solution. Although you...

Initial Host State

Using the Default state configuration, you can determine what happens when the NLB host starts up. If you want the host to immediately join the cluster when Windows starts up, then you should select the Started option. If you want the host to start and not join the cluster until you manually join the cluster, then you should select the Stopped option. If you want the host to start without joining the cluster and enter a suspended state, then you can select the Suspended option. Note that when...

Cluster Service Configuration

Cluster Service Setup Error

In this section, you launch and configure the Cluster Service. In Windows Server 2003, you'll notice you no longer install the service for clustering. This is, by default, already installed when you install the Windows Server 2003. If you look in the Administrative Tools folder located within your Start menu, you'll find the Cluster Administrator Console already installed. Launch this icon and begin to configure the Cluster Service 1. The Cluster Administrator as seen in the next illustration...