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When building a new application or updating an existing one, the load balance is one of the most important factors you need to take into consideration. 

In order to optimize the concurrent usage of your application, it is important to balance the load across all servers. There are a few ways to do this, but one of the simplest is to use a load balancer. In this article, we will be discussing how to balance the load for concurrent usage in your application. Concurrent usage means that there is more than one user using the same application at the same time to execute separate transactions at the same time. It is usually only monitored for a brief period of time. Concurrent user estimation is a measure used for capacity management, performance optimization, resource scaling, licensing definition, and load testing. When there is a lot of concurrent usage, it can be difficult to keep the system running smoothly

The basic formula for calculating concurrent users is as follows:

Per Day visits / Peak hours * (60/Average length per visit in minutes) = Concurrent users

Load balancing

There are many ways to balance the load on an application when it is running in concurrent mode. This can be done by using different algorithms, using different chunks of data, or by using different parts of the application. The most important thing is to make sure that the overall load on the system is balanced.

Load balancing is the technique of distributing network traffic efficiently over several servers, commonly referred to as a server farm or server pool. By equally dividing the demand, load balancing enhances application responsiveness and availability. It has evolved into a requirement as applications get more complicated, user demand increases, and overall traffic increases.

The most basic approach of growing an application server architecture is through load balancing. New servers may simply be added to the resource pool as application demand grows, and the load balancer will begin directing traffic to the new server right away.

As application demand grows, additional servers may simply be added to the resource pool, and the load balancer will begin routing traffic to the new server instantly.

Load Balancer

A load balancer is a hardware or software component that distributes network or application traffic among several servers in a cluster. A load balancer functions as a "traffic cop," taking incoming network and application traffic and directing requests to various backend servers capable of satisfying those requests. A load balancer decreases individual server stress and prevents any one application server from becoming a single point of failure by balancing requests across numerous servers.

Load Balancer characteristics:

• When a single server fails, the load balancer automatically removes it from the server group and transfers the traffic to the remaining active servers.
• When a new instance is introduced to the server cluster, the load balancer begins sending requests to it automatically.
• When a new instance is introduced to the server cluster, the load balancer begins sending requests to it automatically.
• Distributes client requests or network load among numerous servers efficiently.
• Assure high availability and dependability by routing requests to only online servers.
• Can be introduced at several stages of the application architecture (application server, databases, and caches, for example).
• Can add or delete servers from the group dynamically without interfering with current connections.
• While routing requests to several backend servers, the load balancer makes two decisions on which server to use. Confirm that the server they chose is responding before selecting one from a pool of healthy servers using a pre-configured algorithm.
• Confirm that the server they chose is responding before selecting one from a pool of healthy servers using a pre-configured algorithm.
• To guarantee that traffic is routed to only healthy servers, "health checks" try to connect to backend servers on a frequent basis to confirm they are listening. If a server does not pass a health check, it is automatically withdrawn from the pool, and traffic is not sent to it until it passes the health checks again.

Algorithms for Load Balancing:

• Round Robin - When a request is received, the load balancer allocates it to the first server on the list and then pushes that server to the bottom of the list.
• Least Connections – A fresh request is routed to the servers that have the fewest current client connections. When deciding which server has the fewest connections, the relative processing capacity of each server is taken into account.
• Least Response Time — Sends traffic to the server that has the least active connections and the quickest average response time.
• The Least Bandwidth Method - Identifies the server that is currently serving the least volume of traffic (measured in megabits per second) (Mbps)
• IP Hash - The client's IP address is used to decide which server gets the request.
• Session persistence - Also known as a sticky session, is a feature of certain commercial load balancers that routes all requests for a given session to the same physical server that handled the first request for that session in order to enhance speed.

When upstream servers cache information requested by a user to improve performance, moving servers causes that information to be retrieved a second time, resulting in performance inefficiency that may be eliminated by employing session persistence.

Benefits

If your company operates high-traffic websites, apps, or databases that get a significant volume of inquiries, load balancing provides several advantages by improving resource utilization, data delivery, and response time. Load balancing is what ensures that user requests are processed smoothly and correctly in high-traffic scenarios. They save users from having to deal with unresponsive programs and resources. Load balancers enhance application stability and availability by monitoring the "health" of applications and directing requests only to servers and apps that can react quickly.

Load balancing is also important for minimizing downtime and simplifying security, lowering the chance of lost productivity and earnings for your company.

Load balancing also has the following advantages:

• Flexibility: In addition to diverting traffic to maximum efficiency, load balancing allows you to add and remove servers as needed. It also allows for server maintenance to be performed without causing user inconvenience since traffic is diverted to other servers during maintenance.
• Scalability: As the usage of an application or website grows, the increase in traffic may have a negative impact on its performance if not controlled appropriately. Load balancing gives you the flexibility to add a physical or virtual server to meet demand without disrupting service. As additional servers come up, the load balancer identifies them and incorporates them into the workflow effortlessly. This method is preferable to migrating a website from an overburdened server to a new one, which often necessitates considerable downtime.
• Load balancing offers built-in redundancy by dividing traffic among a set of servers. If a server fails, you may immediately divert the load to other servers that are up and running to minimize the effect on users.
• By distributing user requests among many destinations, application load balancing provides the duties of traditional load balancers. However, unlike conventional load balancers, which only function with IP addresses, application load balancers concentrate on content, using URLs, cookies, and HTTP header information to select which target to deliver each user request to.
• Application load balancers also do health checks on each target to ensure it is not suffering any problems. Load balancers send traffic to healthy targets based on the findings to guarantee that the user request is completed rather than being slowed down by an unhealthy target.

Load Balancer Capabilities:

• L4 Load Balancer: Guides traffic based on data from network and transport layer protocols such as IP Address and TCP Port.
• L7: (Load balancing and Content Switching) Load Balancer: Determines routing depending on the application layer data and properties such as HTTP headers, consistent resource identifiers, SSL session IDs, and HTML form data.
• GSLB (Global Server Load Balancing): Extends the fundamental L4 and L7 capabilities to allow them to be used across globally dispersed server farms.

Load Balancer (Hardware) vs. Load Balancer (Software)

• Hardware Load balancers run proprietary technology that is put into a system and frequently optimizes using a specialized CPU.
• Scalability is difficult since we need to add more hardware as load grows.
• Due to the high cost of purchasing and maintaining a physical load balancer, it is quite expensive. A qualified expert is also required for maintenance and operation.
• Increased security as a result of physical hardware

Software load balancers

• Typically, software load balancers run on less costly commodity hardware. It can be deployed and run in any public or private cloud.
• Since it works on commodity hardware, it is less costly.
• Scalability is simple by running more instances of the load balancer.
• Adaptability in response to changing demands
• Can run almost everywhere
• Some intelligent software-based load balancers provide predictive analytics to identify traffic bottlenecks.

Redundant load balancers:

Redundant load balancers: We can deploy more than one load balancer on multiple physical computers in the same cluster to avoid a single point of failure. If the primary load balancer fails, the secondary load balancer takes over.

Important points to consider:

• When it comes to applications, the number one priority is always ensuring that the users are able to get their work done as quickly and efficiently as possible. However, this doesn't mean that the application can't be load-balanced in order to accommodate a concurrent user base. By balancing the load across multiple servers, you can ensure that each user has an equal chance of being serviced in a timely manner.
• There are a few things to keep in mind when implementing load balancing for your application. foremost of which is figuring out how many servers you need and what role each will play. Additionally, you'll want to make sure that your applications are resilient to failures; if one server goes down, there should be another available to take its place.
• There are many ways to balance the load for concurrent usage in an application. One way is to use a load balancer. Load balancers distribute the traffic among several instances of an application. Each instance handles a certain amount of traffic and when it becomes overloaded, the load balancer redistributes the traffic to other instances. In addition to balancing the load, using a load balancer can also improve performance because it can scale up or down based on demand. 
• Balancing load for concurrent usage in an application can be difficult. There are a number of factors to consider, such as the number of concurrent users, the type of data being accessed, and the number of servers involved. In this article, we will discuss some of these issues and how to address them.
• It is important to remember that not all users will require the same level of service at all times. For example, a user who is making small requests should not be competing with a user who is requesting large amounts of data. It is also important to keep in mind the overallocation factor: how much load can each server handle before it becomes overloaded or crashes.

Conclusion

There are many ways to balance the load for concurrent usage in your application. By following the guidelines in this article, you can provide a better experience for your users by ensuring that your application is able to handle the load. In conclusion, by following the tips provided in this article, you can successfully balance the load on your application and improve its performance. Remember to test your changes thoroughly before releasing them into production. And finally, always keep scalability in mind when designing your application. Follow us on https://www.linkedin.com/company/bayshoreintel for more such informative posts.