High CPU and memory usage during server operation is a common problem encountered by many system administrators, website owners, and even beginners. It can range from slow website or business access to frequent service crashes, system unresponsiveness, and even data loss. Therefore, understanding the causes of high CPU and memory usage and mastering a systematic and practical solution is crucial for ensuring stable server operation.

　　In a server, the CPU can be understood as the "brain," responsible for handling all computational tasks, while memory is the "workbench," used to temporarily store data needed by programs. High CPU usage means that the speed of request processing is approaching or has reached its limit; high memory usage indicates that programs running in the system are consuming too much memory space, leaving less room for new tasks. The two often influence each other; for example, insufficient memory can cause the system to frequently use swap space, further increasing the CPU load.

　　Many beginners, upon seeing a spike in CPU or memory usage on their server monitoring panel, often immediately assume "the server configuration is too low." While insufficient configuration is indeed a possible cause, in actual operation and maintenance, it's more often due to improper program, environment, or usage patterns. Blindly upgrading the configuration without first identifying the cause not only increases costs but may also mask the real problem, leading to high usage recurring later.

　　Regarding high CPU usage, one of the most common causes is an excessive number of processes or abnormal processes. Every running program on a server consumes CPU resources. If many unnecessary services are running simultaneously, the CPU load will naturally increase. For example, a server intended only for running a website might have multiple test services, development tools, or legacy programs running concurrently. These seemingly insignificant processes combined can result in significant resource waste. Additionally, some programs may have issues at the code level such as infinite loops, frequent polling, or unreasonable calculation logic, causing a single process to consume a large amount of CPU for an extended period.

　　High memory usage has even more diverse causes. Common situations include memory leaks in the program itself or excessive cache usage due to improper configuration. Memory leaks refer to a program continuously requesting memory during runtime but failing to release it promptly. Over time, the occupied memory increases until the system is overwhelmed. Caching mechanisms are designed to improve performance, but if the cache size is uncontrolled or the caching strategy is inappropriate, it can also consume system memory and affect normal service.

　　When troubleshooting, the first step should be to determine whether high CPU usage, high memory usage, or both are high. This can be done using server-side monitoring tools or cloud provider dashboards to view overall trends and determine whether the problem is intermittent or persistent. If it's just a short-term fluctuation, such as a spike in CPU usage during peak access times followed by a return to normal, this is usually normal and not a cause for concern. However, if it remains high for an extended period, further analysis is needed.

　　The next step is to pinpoint the specific process consuming resources. By viewing the list of currently running processes using system tools and sorting them by CPU or memory usage, the culprit can be easily identified. For beginners, don't rush into complex commands. First, identify the processes consuming the most resources, note their names and purposes, and then analyze their behavior. If you find a process you don't recognize or are sure you no longer need, consider stopping or uninstalling it.

　　If the CPU or memory consumption is due to business-related programs, such as web services, database services, or background tasks, then you need to start with configuration and usage. For example, a sudden increase in traffic, malicious requests, or frequent crawler access can all cause a rapid rise in CPU usage. In this case, you can reduce the consumption of the server by limiting the number of concurrent connections, enabling access frequency limits, and configuring firewall rules. For database services, too many slow queries, missing indexes, and frequent full table scans will significantly increase CPU and memory pressure. Optimizing the database structure and query statements is often more effective than simply expanding the server's capacity.

　　Regarding memory, if you find that memory is almost exhausted, but the server does not have obvious high concurrency access, you should focus on checking for memory leaks in the program. You can observe whether memory usage drops rapidly by restarting the relevant services. If memory usage rises rapidly again shortly after restarting, it's likely a program issue. In this case, consider upgrading the program version, fixing known vulnerabilities, or contacting the developers for code-level investigation. If the issue cannot be fixed temporarily, you can alleviate it by periodically restarting services or limiting the maximum memory used by a single process, but these should only be temporary solutions.

　　When memory is insufficient, the system usually uses swap space to relieve pressure. However, swap space essentially uses disk space to simulate memory, which is much slower than physical memory. Frequent use of swap space will significantly degrade overall server performance, and CPU load may increase. Therefore, properly configuring swap space and avoiding prolonged and excessive use is crucial for ensuring server stability.

　　Besides program and configuration issues, security factors are equally important. Malicious attacks on servers or the implantation of mining programs are typical scenarios leading to persistently high CPU usage. These situations often manifest as abnormally high CPU utilization, even with low traffic. If suspicious processes are discovered during troubleshooting, and their resource usage is unrelated to business operations, immediate action should be taken. This includes terminating the processes, checking for system vulnerabilities, changing important passwords, updating system patches, and even reinstalling the system if necessary to ensure a clean and reliable server environment.

　　After initially resolving the issue, long-term prevention is crucial. First, develop the habit of regularly monitoring the server to promptly identify abnormal trends, rather than waiting for service crashes to occur. Second, plan server configurations rationally, gradually expanding resources according to business growth to avoid prolonged operation at resource limits. Third, keep the system and software updated; many performance and memory issues have been optimized in newer versions, and timely upgrades can save significant troubleshooting costs.

　　For beginners, it's also important to understand that high server CPU and memory usage is not an "unsolvable problem," but rather a signal indicating an irrational system. By following a step-by-step approach—from symptom to cause, and from cause to solution—you will eventually find the breakthrough. Instead of rushing to expand capacity, optimize existing resources first. This not only improves server stability but also helps you gain a deeper understanding of server operating mechanisms.

　　In general, there is no single, universally applicable solution to high CPU and memory usage issues on servers; each issue requires analysis based on the specific business scenario and server environment. However, by grasping the basic principles and learning how to observe, locate, and verify, you can handle similar problems with greater ease. With experience, you'll find that many seemingly intractable high-utilization issues actually stem from preventable small details, and these details are precisely the key to stable server operation.