By Ravi Duddukuru

Ensuring that your web application provides an excellent user experience could be a full time job. Using a load balancer, you can efficiently improve your web application’s user experience by optimizing the resources you have.

Traditionally, they’re deployed as hardware load balancers, but as technology improves and space runs out, load balancers are now often deployed as software or in an application delivery controller (ADC).

Besides a load balancer, an ADC is packaged with other network-based tasks, such as SSL offloading, caching, and web application firewalls. However, its main functionality is still load balancing.

Why Is It Important to Use Load Balancing for Your Web Application?

The main purpose of load balancing is preventing a server overload and maintaining a healthy amount of activity in each server. By balancing incoming requests and the power provided by the resources, a load balancer creates a highly available, scalable, and reliable web application for your users.

Load balancers for web application servers are normally placed between your backend servers and your firewall. Using a load balancer, which distributes client requests to available servers, lets you handle high traffic conditions with zero downtime. It also provides better accessibility and responsiveness for concurrent users.

Load balancers optimize your servers’ capacity rather than adding more and more resources to improve your application’s performance.

Besides managing traffic moving between servers, you can also manage multiple data centers in various locations using a global server load balancer (GSLB).

Benefits of Load Balancing on Web Servers

Reduce downtime

Implementing load balancers can significantly reduce your downtime. Three scenarios can be prevented using load balancers:

1. Server overload – which can occur for a multitude of reasons, such as a DDoS attack, too much traffic, or even broken servers.

2. Maintenance – but your application can stay online with a load balancer’s support, which will redirect your traffic to another server.

3. In the event of a failure – your load balancer also provides a built-in redundancy by redirecting traffic to your backup system while recovering your servers.

Improve scalability

Website scaling can be described as your website’s ability to perform well even under heavy traffic. Load balancers, which are used to distribute traffic efficiently across the available servers, are key players in improving your application’s scalability.

Load balancers improve the capacity of existing servers. It’s a more sustainable way of enhancing scalability than blindly adding more servers.

Security and compliance

Load balancers give an additional layer of security to your network system. They redirect and filter malicious traffic (such as one from a DDoS attack) to a public cloud provider.

Using a load balancer also simplifies PCI compliance, which is a requirement for websites that process credit cards.

Database Load Balancing

Database load balancing is a reverse proxy located between an application and its database servers. By distributing database workload across multiple computing resources, database load balancers are used to improve the performance of web applications efficiently.

As part of the load balancer architecture, it has a similar purpose as server load balancers: to optimize the performance of web applications by avoiding resource overload.

Based on the interconnection model, there are two types of database load balancers: Layer 4 and Layer 7.

1. Load balancers that work in Layer 4 make routing decisions based on IP addresses and UDP or TCP ports.These types of load balancers can only make decisions based on traffic data, which is why it’s faster than load balancers in Layer 7. Some examples of load balancers that can operate in Layer 4 are HAProxy and Nginx.

2. In layer 7, the load balancer works at the application layer, making it privy to packet data.It’s more time-consuming since you need to make routing decisions based on specific data. It also gives you more efficient features, such as database connection pooling or query caching. Some examples of load balancers that can operate in layer 7 are ScaleArc, ProxySQL, and Citrix.

The load balancing algorithm used by a database load balancer is similar to ones in a server load balancer, such as:

1. Round robin: the load balancer goes through a list of servers to determine where to send the traffic
2. Least connections: the load balancer sends traffic to the server with least active connections.
3. Least response time: the load balancer sends traffic to the server with the least response time during health checks.
4. IP hashing: the load balancer generates a unique key based on the client’s IP address to allocate all traffic from the address to a certain server.

Unlike server load balancers, however, there are some prerequisites you need to fulfill before using a database load balancer: the databases you’re using need to be synchronized and have the same data.

Otherwise, you’ll have different answers for the same query, compromising your application’s precision.

Companies Using Load Balancers for MySQL & Microsoft SQL Server

1. Mouser

Mouser Electronics is a worldwide leading company in semiconductor and electronic components distribution. Founded in 1964, Mouser has plenty of experience in its field and is the seventh largest electronic component distributor in the world. Its eCommerce website serves people all over the globe and needs to be online 24×7.

To minimize downtime in case of hardware failure or maintenance, Mouser Electronics needed a load balancer that can help with maintaining Mouser’s eCommerce website during the failover. Using ScaleArc and SQL server, Mouser has managed to achieve continuous availability and zero downtime since 2014.

1. BookMyShow

BookMyShow is the largest ticketing platform in India and several other Asian countries. It’s a platform that lets users buy tickets for movies, sports, events, plays, and other activities.With normal traffic, BookMyShow gets over 400 million page views monthly. However, during peak season, the traffic could shoot up exponentially and overload the servers. To keep up with the transaction demand and uphold performance, BookMyShow used ScaleArc with SQL server to boost BookMyShow’s database capacity.

1. DataposIT

DataposIT Limited manages the IT infrastructure for business applications. It helped a government agency in Kenya with managing health information that will be used to combat HIV/AIDS in Kenya.DataposIT used NGINX Plus and MySQL to improve the reliability of the application, as well as improve their failover system. With the help of a load balancer, DataposIT can improve the uptime of the application.

1. Nasdaq

Nasdaq is the creator of the first electronic stock market. As a leader in the financial industry, Nasdaq’s business needs to be accessible all the time and available all around the globe.Nasdaq needed to upgrade to a system with high availability from its legacy infrastructure, with zero downtime. With the help of ScaleArc and SQL server, Nasdaq managed to improve its performance, migrate to a highly-available infrastructure, and add app-transparent failover.

What to Consider Before Choosing A Load Balancer

Total Cost of Ownership

The load balancing software cost depends on the type of load balancer you choose and the load balancing architecture used. Naturally, a more complex architecture will cost more, as it requires multiple load balancers, initial setup costs, and ongoing maintenance costs.

There are also elastic load balancers (or cloud load balancers), such as the one provided by AWS, which often uses a subscription-based model, and open source load balancers, such as HAProxy and Nginx.

Centralized management

Having one platform to access and control your traffic, insight, and configuration can be extremely helpful, especially if your application is deployed across multiple environments.

Centralized management makes it easier to manage your traffic and provides a space for combined insights across regions and environments for better analytics.

Scalability

Understanding what you need to do to scale your balancers up and down prepares you for the eventual process. Ideally, you don’t want to go through a lot of hassle like adding another physical hardware to scale your load balancers. At times, you’ll also need to change the configuration of your load balancer when scaling.

Security

As a focal point in your system, load balancers can turn into a weakness if not properly protected. Ensure that the solution you’re choosing has reasonable protection included and a failover system to support it.

Insights, Monitoring, & Reporting

Often, load balancers also come with insights on your network data. The analytics provided by your load balancers can help you make smarter business decisions.

Automation

Checking the option to automate your load balancing and provisioning tasks should also be considered if you want to lessen your workload in the future.

Support & Training

How much support you received and the training needed to maintain a load balancer also comes into play. If you need a complex load balancer setup, it’s a given that you’d like experts to help you set up, configure, and maintain your load balancer, as it’s a crucial point in your system.

Optimizing Your Resources with ScaleArc

Database and web server load balancing can be hard to maintain.

However, implementing a load balancer in your infrastructure can help you attain high performance, availability, and flexibility.

Improving the capacity of your database is easy if you have a dependable load balancer like ScaleArc. Create a platform with zero downtime by using ScaleArc to create an excellent failover system and plan for disaster recovery before failure happens.

If you’re interested in all the benefits a database load balancer offers, try ScaleArc right now.

This blog Originally appeared on Devgraph.com