Isn’t it necessary to balance the load in whichever situation you are in? Keeping things in balance is a concept that applies to nearly everything we do, whether we realize it or not.
Taking an example for balance, a lot of workplace culture focuses on the concept of balance. For this discussion, I’m referring to the harmony between one’s professional and personal life. If professional and personal life is not balanced, one or the other thing is ought to get hampered.
Similarly, balance plays a vital role in server management or web hosting. Balance is indeed essential when you are hosting a website or dealing with servers.
The term “load balancing” is rumored about these days, but few people truly grasp what it means or why it is so crucial.
Load Balancing in Terms of Servers/ Dedicated Servers
Load balancing is the process of intelligently distributing traffic among multiple physical servers to maximize resource utilization. In other words, the process of sharing computing workloads between two or more computers/servers is load balancing. This basically minimizes the load on each server and increases its efficiency, resulting in faster performance and lower latency. Most Internet applications require load balancing to work accurately.
How Does Load Balancing Work?
A load balancer is a tool or program that handles load balancing. A load balancer is made of either hardware or software. Software-based load balancers can run on a server, a virtual machine, or in the cloud, whereas hardware load balancers require the installation of a specialized load balancing device. Load balancing is a common function of content delivery networks (CDNs).
Hardware vs. Software Load Balancers
The following is how hardware-based load balancers work:
- They’re usually high-performance equipment that can safely process several gigabits of traffic from a variety of sources.
- Built-in virtualization features are included in these appliances, allowing several virtual load balancer instances to be consolidated on the same hardware.
- Hardware load balancers enable more flexible multi-tenant designs and complete tenant isolation.
The following is how software-based load balancers work:
- Can completely replace load balancing hardware while maintaining similar functionality and flexibility.
- They may operate on popular hypervisors, in containers, or as Linux processes on bare-metal servers with minimum overhead. They’re extremely customizable based on the use cases and technological needs.
- Help save space and money on hardware.
The load balancer allocates each request to a precise server as it comes in from a user, and this procedure repeats for each request. Load balancers use a variety of algorithms to determine which server should handle each request.
The load balancing algorithms are divided into two sections:
- Static load balancing algorithms
- Dynamic load balancing algorithm
Static load balancing algorithms
Static load balancing techniques distribute workloads without regard for the system’s present state. A static load balancer has no way of knowing which servers are sluggish and which ones are underutilized. Instead, it distributes responsibilities according to a predefined schedule. Although static load balancing is simple to set up, it might cause inefficiencies.
Round Robin is one of the examples of static load balancing method
Dynamic load balancing algorithm
Dynamic load balancing methods take into consideration each server’s current availability, workload, and health. These algorithms redirect traffic from overcrowded or underperforming servers to underused servers, ensuring equitable and efficient distribution. Dynamic load balancing, on the other hand, is more complex to set up. Server availability is determined by a variety of factors, including the health and overall capacity of each server, the amount of the distributed tasks, and so on.
There are many different kinds of dynamic load balancing algorithms, such as least connection, weighted least connection, resource-based, and so on.
Some Load Balancing Algorithms
The Round Robin Method
The Round Robin approach is the simplest of the balancing techniques. Requests are forwarded one by one to each server in the architecture, ensuring that traffic is spread fairly. When the algorithm has gone through the whole list of instances/servers, it returns to the top of the list and starts over.
The Least Connections Method
The least connections technique is a default load balancing mechanism that sends incoming requests to the server with the fewest active connections. This is the default load balancing approach since it provides the greatest performance in the majority of situations. The least connections technique is ideal for cases when server engagement time (the length of time a connection is active) varies.
Weighted Least Connections
The weighted least connections approach, which is also accessible with the Round Robin method (it’s called the weighted Round Robin method), allows each server to be granted a priority status.
Source IP Hash
When a load balancer utilizes a source IP hash, each request from a single IP address is given a key, which is then allocated to a server.
Source IP hash not only distributes traffic fairly across the infrastructure but also ensures server consistency. Once issued, a unique IP will always connect to the same server.
The URL hash technique assigns keys based on the requested IP rather than the arriving IP.
The Least Response Time Method
The least response time technique, like the least connections method, distributes requests based on the number of connections on the server as well as the lowest average response time, lowering a load by integrating two levels of balancing.
The Bandwidth and Packets Method
The Bandwidth and Packets methods of virtual server balancing distribute requests to the load balancer based on which server is coping with the least amount of traffic (bandwidth).
The custom load method necessitates the use of a load monitor. It assigns requests based on a variety of server characteristics (including CPU utilization, memory, and response time, among others).
Least Pending Requests (LPR)
HTTP/S requests are monitored and delivered to the most available server using the technique of the least pending request. The LPR technique can manage a large number of requests at the same time while keeping track of each server’s availability.
Use of Load Balancing
Web applications frequently utilize load balancing. Load balancers, both software, and cloud-based assist distribute Internet traffic evenly across the servers that host the application. Global server load balancing (GSLB) is a feature of cloud load balancing systems that allow them to balance Internet traffic loads among servers globally.
Load balancing is also prevalent in localized networks, such as data centers and huge office complexes.
Traditionally, hardware appliances such as an application delivery controller (ADC) or a dedicated load balancing device were used.
Dynamic load balancers must be aware of server health, including their present status, performance, and so on. Server health monitoring is performed regularly by dynamic load balancers. The load balancer sends less traffic to a server or group of servers that operate poorly. The load balancer reroutes traffic to another set of servers whenever a server or group of servers fails altogether, a process known as “failover.”
What Exactly is Failover?
Failover happens when a server stops working, and a load balancer transfers its regular activities to a different server or set of servers. Server failover is critical for uptime: without it, a server crash might bring a website or service to a halt. Failover must happen promptly so there’s no downtime.
Finally, a Word on Load Balancing
No matter what your aim is, if you’ve outgrown a single web server (or are about to), you’ll profit from a load balancer since it will keep your website and data available, operating, and performing at their best. Even if you choose a managed system rather than implementing it yourself, knowing your needs, existing systems, and where you want to go ultimately can help you make smarter business decisions.