How does a Load Balancer allow a website to scale?
Server load balancing is the process of distributing network traffic more evenly across several servers. This way, users will access the website with approximately the same speed and success, and no server will become overtaxed unless the traffic is truly exceptional.
Using a Server Load Balancer for Scalability
When your business starts to become successful, it will usually see a dramatic increase in web traffic. That increase in traffic is one of the biggest trials for your company's website because the site's servers need to be able to withstand the load of all the new traffic.
Your website is vital to your bottom line. A 1-second lag in page load time will result in lost sales. Studies have revealed that 79% of customers who are dissatisfied with website performance are unlikely to buy and that 40% of users will abandon a slow-loading website.
What Is Website Scaling?
Website scaling is the process of ensuring your website remains accessible during increases in traffic. Scalability often goes hand in hand with several other metrics, including availability (or uptime) and the website's speed.
Administrators can test how well a website scales by adding virtual users and monitoring how the website responds. If the website continues working, it scales well under those conditions. If not, administrators may need to do something to increase the server’s capacity.
One of the most common methods of scaling a website involves adding more servers to handle more traffic. However, this solution is usually very expensive and may not solve the problem: If one server is handling a disproportionate amount of traffic compared to the others, many users will see the site slow down or even become inaccessible, no matter how many users there are. To improve the capacity of existing servers, many administrators use a technique called server load balancing.
Different Load Balancing Algorithms
Load balancers use several algorithms to determine where to send a request. No algorithm is perfect, but having multiple options provides the highest availability and reduces risk. Some of the most common load balancing algorithms include:
- Round robin algorithm: Requests are sent to upstream servers in order—i.e., request 1 goes to server A, request 2 goes to server B, and so on. Once a server receives a request, the server moves to the bottom of the queue.
- Least connections algorithm: Requests are sent to the server with the fewest active connections and the highest potential response time.
- IP hash algorithm: Requests are sent to servers based on IP address. This ensures the same client will always be directed to the same server if it is available.
More Server Load Balancer Tips
Just installing a load balancer will have a positive effect on your website. But, for maximum effect, you'll need to take a few additional steps. For instance, make sure your servers are all synchronized to the same time -- preferably by connecting with a standardized atomic clock. Make sure you're measuring all your network activity so you can identify problems or changes as they arise, and set up access lists to restrict traffic.
If you're choosing your first load balancer, consider Snapt Aria. Aria's software load balancer has a lightweight footprint and can be deployed on any cloud (public/private), containers, VM/hypervisor, or bare metal.
Aria can handle upwards of 100,000 TPS where and when they are needed, for any size environment at a scale and cost that suits your business. Our software load balancers are right-sized for your network and workloads at every point in time and are capable of dynamic adjustment to meet ever-changing demands.
No one can predict when a website will be subjected to heavy traffic. But a load balancer is the best way to make sure your website can scale to meet any surges in demand.