Servers abound, this mission-critical hardware is a key driving force behind countless technologies ranging from networks and software, to mobile applications, websites and beyond. Server overload and subsequent crashes can be extremely problematic, with companies losing countless millions as a direct result of this downtime.
Load balancers can serve as a very effective tool for preventing server overload and avoiding downtime. But this leaves many business leaders wondering how load balancing works, while others may have questions such as, “How efficient are load balancers in preventing server overload?”
What Are Load Balancers and How Does Load Balancing Work?
Load balancers emerged as a hardware-based technology that required proprietary software. A company had to acquire and maintain on-premises servers, accounting for significant overhead in the form of a data center. The costs of maintaining and staffing a data center are significant so only the largest companies were able to utilize load balancing technology.
Over time, new and more financially-feasible load balancing solutions emerged, allowing smaller companies and even startups to benefit from load balancing technology. Today’s cloud-based technology allows for the use of virtual machines in load balancing configurations, offering a scalable and affordable option.
The load balancing process prevents a “clump” of incoming clients requests from overloading a single server. Load balancers have a central hub server — the actual load balancer — that works by intercepting the incoming requests. Those client requests are then evaluated by the hub server using a predefined protocol, also known as a load balancing algorithm. This algorithm determines how the client requests are evaluated and then distributed across a pool of servers.
Many load balancers also perform server health checks, which serve to improve performance and even user experience. Health checks are used to detect poor availability and identify ailing servers. If a problem is detected, the affected server is removed from the pool and flagged for maintenance. These server health checks are very effective for ensuring that only well-performing servers are in use within the pool. Health checks also reduce the incidence of error messages, thereby improving user experience.
But this begs the question: What is server overload? And how efficient are load balancers in preventing server overload?
What is Server Overload and What Are the Consequences?
Server overload occurs when a large number of incoming client requests overwhelm a server’s available resources. The server is unable to keep up with demand. At first, sluggish performance tends to be the most noticeable symptom of server overload. Consistent overload or extreme demand may cause the server to fail completely, resulting in downtime for both the server and all of the technologies that rely upon that server. Software platforms and mobile apps may crash. Website pages will fail to load and those frustrating error messages are served up to users. Networks will cease to function, making it impossible to transmit data. The impacts of server overload can be extremely problematic and far reaching, especially in the case of mission-critical systems.
Slowed performance aside, the symptoms of server overload may include the following.
Error Codes – HTTP error codes are a common sign of an overloaded server. The most commonly-encountered codes are 408, 500, 502, 503 and 504.
Failed TCP Connections – Transmission control protocol (TCP) connections facilitate a channel for communication between the client and the server. A faltering and overloaded server may reset, drop or deny TCP connections, making it impossible for data to travel back and forth between the client and server. As a result, the server-reliant technology ceases to function properly.
Delays in Serving Up Client Requests – A server can only handle a finite number of client requests at one time. A large volume of incoming client requests can result in a backlog of sorts. Incoming server requests must wait in line, so to speak, leading to a delay in the server’s “reply.” On the client’s end, this manifests as slowed performance like sluggish website page loads. You may also observe partial and incomplete loads of content. Serving delays of one second or more are suggestive of overload.
How Efficient Are Load Balancers in Preventing Server Overload?
When it comes to the matter of efficiency in preventing server overload, load balancers are extremely effective. They target a chief cause of downtime as they distribute incoming traffic across multiple high-performing servers with high availability. This prevents an overload scenario.
Any IT admin can tell you that server overload is a very real problem and a common cause of performance issues. Server overload causes downtime that can leave a company without mission-critical technology, resulting in productivity losses and financial losses. Those with consumer-facing technology — think subscription-based mobile app or a SaaS offering via a web-based portal — stand to lose paying users or subscribers. Server overload causes sluggish performance or crashes that, in turn, leave users feeling as though the platform is glitchy and unreliable. As a result, users may cancel subscriptions and take their business elsewhere. Overcoming a reputation of poor performance can be extremely challenging and this can have a very negative impact. People may be more reluctant to become a paid user or subscriber. This can translate into major long term financial losses for a mobile app, SaaS offering or any other platform that leverages server technology.
While load balancers are extremely effective at preventing server overload, you need the right load balancer if you’re going to see the maximum benefits. There are many different types of load balancers and even more load balancing algorithms to consider. Choosing the right load balancing solution and configuration is key. The team at Resonate is available to provide consultation to clients as they seek out the ideal load balancing technology for their needs.
At Resonate, we offer a range of different load balancing solutions that deliver exceptional performance, unmatched reliability and optimal scalability. We invite you to reach out to the Resonate team today to discuss your load balancing requirements and identify the ideal load balancer for preventing server overload and maximizing performance.