Web Server Overload: Causes, Signs, and Prevention

Having a web server become overloaded is an issue that most organizations eventually face, even those with extensive experience in handling server-side matters. For an organization new to diagnosing and responding to server problems, however, an overload can be especially disruptive—costing visitors, revenue, and reputation. Here we list some of the common causes and tell-tale signs of server overload and provide key actions your organization can take to prevent it from happening.

Causes of Server Overload

Web servers can become overloaded at any time due to one of the following reasons: 

• Sudden spikes in site traffic. When too many people attempt to visit your web site at the same time, it can cause your server to become overload. An example of this is when concert tickets go on sale, and the web site crashes soon after. Spikes in traffic can be short-term, but the effects on your business’s reputation can linger.
• One of your servers is completely unavailable. When one server is unavailable due to maintenance or sudden malfunction, the backup server can easily become overloaded while handling the extra traffic.
• Computer viruses or worms. When a large-scale number of browsers or computers become infected by a virus or worm, it can cause abnormally high traffic patterns that disrupt normal server operation.
• DoS or DDoS attacks. Denial-of-service or distributed-denial-of-service attacks are attacks launched by hackers for the purpose of making a server unavailable for its intended users. By flooding the network with false requests, hackers crash the server and cause it to deny the real requests.

Signs of Server Overload

The following signs indicate that your web server has possibly become overloaded:

• Displaying error codes. Your server returns an HTTP error code, such as 500, 502, 503, 504, 408, etc.
• Delaying serving requests. Your server delays serving requests by a second or more.
• Resetting or denying TCP connections. Your server resets or denies TCP connections before it returns any content.
• Delivering Partial content. Your server returns only part of the content that was requested. This could possibly be a bug, or it could also be caused by server overload.

Preventing Server Overload

There are several standard practices to help prevent server overload. These include blocking unwanted incoming traffic using firewalls, providing alternate sources for content delivery via site caching, and designating different servers for handling different file sizes. However, the most effective solution for preventing server overload is to utilize a server load balancing solution.

Load balancing eases the flow of incoming network traffic to each of an organization’s servers by distributing the traffic across the group of servers as a whole. The load balancer resides between the client and the servers, and routes requests according to an algorithm. If one server fails, the load balancer simply redirects traffic to working servers to avoid disruption. Software load balancers excel for their programmability, real-time scalability, reduced cost, application security, and ability to be deployed on-demand.

Saving Time and Money

Overloaded servers can lead to disruptive outages that cost your business time and money. Resonate offers reliable software-based server load balancing solutions. Contact us to learn more about how your business can benefit from our innovative products.