Windows Clustering and Load Balancing, Explained
Monday, March 16th, 2009 | Author:

Clustering in Windows 2003 Dedicated or Shared hosting is a means of providing High Availability to your applications and websites. Clustering is a group of machines acting as a single entity to provide resources and services to the network. In time of failure, a fail over will occur to a system in that group that will maintain availability of those resources to the network. You can be alerted to the failure, repair the system failure, and bring the system back online to participate as a provider of services once more. You learn about many forms of Windows clustering. Clustering in Windows 2003 hosting can allow for failover to other systems and it can also allow for load balancing between systems. Load balancing in Windows 2003 hosting is using a device, which can be a server or an appliance, to balance the load of traffic across multiple servers waiting to receive that traffic. The device sends incoming traffic based on an algorithm to the most underused machine or spreads the traffic out evenly among all machines that are on at the time. A good example of using this technology would be if you had a web site that received 2,000 hits per day. If, in the months of November and December, your hit count tripled, you might be unable to sustain that type of increased load. Your customers might experience time outs,

slow response times, or worse, they might be unable to get to the site at all. With that picture fresh in your mind, consider two servers providing the same web site. Now you have an alternative to slow response time and, by adding a second or a third server, the response time would improve for the customer. High Availability is provided because, with this technology, you can always have your web site or services available to the visiting Internet community. You have also systematically removed the single point of failure from the equation. A single point of failure is removed because you now have a form of redundancy added in.

Pros and Cons to Windows 2003 Clustering and Load Balancing:

You could now be asking yourself, which is better to implement, Windows clustering or load balancing hosting? To give you a quick rundown of the high-level pros and cons to each technology, consider the following. With Windows cluster hosting, you depend on the actual clustered nodes to make a decision about the state of the network and what to do in a failure. If Node A in a cluster senses a problem with Node B (Node B is down), then Node A comes online. This is done with heartbeat traffic, which is a way for Node A to know that Node B is no longer available and it must come online to take over the traffic. With load balancing, a single device (a network client) sends traffic to any available node in the load-balanced group of nodes. Load balancing uses heartbeat traffic as well but, in this case, when a node comes offline, the “load” is recalculated among the remaining nodes in the group. Also, with clustering (not load balancing), you’re normally tied down or restricted to a small number of participating nodes. For example, if you want to implement a clustered solution with Windows 2003 Advanced Server, you might use a two-node cluster. With load balancing, you can implement up to 32 nodes and, if you use a third-party utility, you can scale way beyond that number. You can even mix up the operating system (OS) platforms, if needed, to include Sun Solaris or any other system you might be running your services on. Finally, you have the option to set up tiered access to services and to mix both architectures (clustering and load balancing hosting) together. You can set up the first tier of access to your web servers as load balanced and the last tier of access as your clustered SQL databases.

With eukhost we have expertise for any feature as per your hosting requirement. We can also setup Windows Dedicated Cluster hosting along with Plesk control panel, this is something that only eUKhost can provide.