A server farm is a collection of computers that is used to disperse network traffic using a technique called load balancing. As the demand is evenly divided among several servers and computational resources, it enhances network performance, dependability, and capacity while lowering latency.
In order to determine in real time which server in a pool can best satisfy a particular client request, load balancing makes use of an appliance—either physical or virtual. This prevents a single server from being unnecessarily burdened by high network traffic.
Load balancing offers failover in addition to increasing network capacity and maintaining excellent performance. The impact on end users is reduced when a load balancer promptly switches workloads to a backup server in the event that one server fails.
The Open Systems Interconnection (OSI) communication model’s Layer 4 or Layer 7 are often described as being supported by load balancing. Traffic is divided up by Layer 4 load balancers depending on transport information such IP addresses and TCP port numbers. Routing decisions are made by Layer 7 load-balancing devices based on application-level features, which include HTTP (Hypertext Transfer Protocol) header data and the message’s actual contents, including URLs and cookies. Although Layer 4 load balancers are still ubiquitous, especially in edge deployments, Layer 7 load balancers are increasingly prevalent.
How load balancing works
The inbound requests from users for data and other services are handled by load balancers. They are situated in-between the internet and the servers that respond to such queries. The load balancer first identifies which server in a pool is available and online when a request is received, and then it sends the request to that server. A load balancer responds quickly and can dynamically add servers in response to traffic surges during periods of high stress. In contrast, if demand is minimal, load balancers may remove servers.
Types of load balancers
A crucial part of highly accessible infrastructures is load balancing. Several load balancer types may be implemented with varying storage capacity, functionality, and complexity levels depending on the demands of a network.
A load balancer can be a software instance, a physical device, or a hybrid of the two. There are two different categories of load balancers:
Hardware Load Balancer: A hardware load balancer is a piece of hardware with proprietary, specialised software integrated into it that is made to manage high application traffic volumes. These load balancers allow for the usage of several virtual load balancer instances on a single device due to their built-in virtualization functionality.
In the past, suppliers installed exclusive software on specialised hardware and offered it to customers as stand-alone appliances, frequently in pairs to enable failover in the event that one system fails. Expanding networks need the acquisition of more or bigger appliances by a company.
Software Load Balancer: Software load balancing is often performed by application delivery controllers (ADCs) on white box servers or virtual machines (VMs). Other services offered by ADCs frequently include caching, compression, and traffic shaping. Virtual load balancing, which is common in cloud systems, may provide a great level of flexibility. Users can, for instance, dynamically scale up or down to reflect traffic peaks or drops in network activity.
Cloud-based load balancing
In order to balance cloud computing settings, cloud load balancing employs the cloud as its underlying architecture.
The following are examples of cloud-based load-balancing models:
- Network load balancing. This is the fastest load-balancing option available. It operates on Layer 4 of the OSI model and uses network layer information to transport network traffic.
- HTTP Secure load balancing. This enables network administrators to distribute traffic based on information coming from the HTTP address. It’s based on Layer 7 and is one of the most flexible load-balancing options.
- Internal load balancing. This is similar to network load balancing, but it can also balance traffic distribution across the internal infrastructure.
Benefits of load balancing
Network traffic load-balancing has several advantages for companies that manage numerous servers. The principal benefits of employing load balancers are as follows:
- Improved scalability: Depending on the needs of the network, load balancers may dynamically grow the server infrastructure without impacting services. For instance, if a website starts getting a lot of traffic, traffic may suddenly increase. The website may go down if the web server is unable to handle this unexpected surge of demand. To avoid this, load balancing can distribute the excess traffic among several servers.
- Improved efficiency: The amount of traffic on each server is lessened, which improves network traffic flow and response times. Visitors to the website will eventually have a better experience as a result.
- Reduced downtime: Load balancing has advantages for businesses with a global presence and several sites in various time zones, especially when it comes to server maintenance. To avoid service disruptions or downtime, a business might, for instance, shut down the server that requires maintenance and direct traffic to the other available load balancers.
- Predictive analysis: Early failure identification and management may be accomplished with the use of load balancing, without harming other resources. Software-based load balancers, for instance, may foresee traffic bottlenecks before they occur.
- Efficient failure management: Load balancers may automatically reroute traffic to working resources and fallback choices in the case of a failure. For instance, load balancers can transfer resources to other unaffected locations if a failure is discovered on a network resource, such as a mail server, to prevent service interruption.
- Better security: Without needing additional modifications or resources, load balancers offer an additional layer of protection. A security feature known as offloading is being added to load balancers as more computing goes to the cloud. By redirecting attack traffic from the corporate server to a public cloud provider, this protects an organisation from distributed denial-of-service assaults.
