Common problems
Things that can go wrong on a Linux server
Running a Linux server on the internet can be complicated, and many things can go wrong. Don't worry, we'll not only explain the common problems, but also show you how to diagnose and solve them:
Data corruption: Data corruption can affect single files, a database, or the whole file system. It can be caused by various factors and may be difficult to diagnose.
Database issue: Database issues can cause problems such as poor performance, data loss, or unexpected behavior. This can happen due to software bugs, hardware failures, or incorrectly configured databases.
Data breach: A data breach occurs when sensitive, confidential, or protected information is accessed, stolen, or exposed without authorization. This can happen due to various causes, such as cyberattacks, weak security controls, or human error. Data breaches can lead to identity theft, financial loss, legal consequences, and reputational damage. Implementing strong encryption, regular security audits, and employee training can help reduce the risk of breaches and safeguard critical data.
Denial-of-service: A Denial-of-Service (DoS) attack occurs when a system is overwhelmed with a flood of traffic or requests, making it unavailable to users. This can happen through a variety of methods, including overloading network resources, exploiting software vulnerabilities, or triggering crashes. Proper rate limiting, firewall configurations, and monitoring can help mitigate these attacks and ensure availability.
Disk failing: SSDs can alert you, when they reach their end of life. Then it's time to react quickly to avoid data loss.
Disk full: Running out of disk space can cause a variety of problems, such as preventing new files from being written or causing system crashes.
DNS issue: DNS issues can cause problems such as difficulty in resolving domain names, poor performance, or unexpected behavior. This can happen due to misconfigured DNS settings, network connectivity issues, or hardware failures.
Email issue: Email issues can cause problems such as difficulty in sending or receiving email, poor performance, or unexpected behavior. This can happen due to misconfigured email settings, network connectivity issues, or software bugs.
File not found: A "File not found" issue occurs when a requested file is missing or has been moved. This can lead to errors such as system crashes, application failures, or inaccessible resources. Common causes include accidental deletion, incorrect file paths, or corrupted directories.
File system corruption: File system corruption is a special case of data corruption. it can cause data loss and system crashes, and can be caused by a variety of factors such as power outages, software bugs, or hardware failures.
Firewall issue: Firewall issues can cause problems such as poor performance, unexpected behavior, or difficulty in accessing remote resources.
Hardware failure: Hardware failures can cause a variety of problems, such as system crashes, data loss, or unexpected behavior.
High I/O wait: If the CPU needs to wait for data from disk, the system may become very slow or unusable.
High load: A high load can cause system slowdowns and unresponsiveness, and can be caused by a number of factors such as malware, resource-intensive processes or bugs in software.
High memory usage: When the running processes use a lot of the available RAM, it may not be possible to start additional applications. Even worse, if you run out of available memory, the kernel might kill one or more processes to free some memory.
Incorrect configuration: Incorrect configuration of software or services can cause a variety of problems, such as system crashes, unexpected behavior, or poor performance.
Incorrect time: Incorrect system time can lead to various issues, such as problems with authentication protocols, certificate validation errors, or failure in syncing processes. Time-sensitive applications may experience unexpected behavior, and network communications could be disrupted if the system clock is out of sync with other systems. Common causes include misconfigured time settings, network time protocol (NTP) errors, or incorrect hardware clocks.
Kernel issue: Kernel issues can cause problems such as system crashes, poor performance, or unexpected behavior. This can happen due to software bugs, hardware incompatibilities, or outdated kernels.
Kernel panic: A Kernel panic occurs when the system cannot recover from an error. In this case, the Kernel will intentionally stop running to prevent further damage, rendering the system unusable.
Malware infection: Malware infections can cause a variety of problems, such as data loss, system crashes, or unauthorized access to a system.
Memory leak: Memory leaks occur when a process continues to consume more and more memory over time, eventually causing the system to run out of memory.
Network failure: Network issues can cause problems such as slow performance, intermittent connectivity, or complete loss of connectivity, which can be caused by a variety of factors, such as misconfigured network settings, hardware failures, or security breaches.
NTP issue: NTP issues can cause problems such as difficulty in synchronizing time, unexpected behavior, or poor performance. This can happen due to misconfigured NTP settings, network connectivity issues, or software bugs.
Out of Memory: This problem can be caused by configuration errors, Memory leak, or when too many processes are started and cannot finish on time during High load phases.
Permissions issue: Permissions issues can cause problems such as difficulty in accessing resources, unexpected behavior, or poor performance. This can happen due to misconfigured permissions settings, software bugs, or hardware failures.
Poor performance: Poor performance can be caused by a variety of factors, such as high load, resource-intensive processes, or software bugs, and can cause system slowdowns and unresponsiveness.
Power issue: Power issues can cause problems such as system crashes, data loss, or unexpected behavior. This can happen due to power outages, hardware failures, or software bugs.
RAID member inactive: When a drive is missing from a RAID array, you need to find a replacement to avoid data loss.
Security breach: Security breaches can cause problems such as data loss, unauthorized access, or system compromise. This can happen due to weak passwords, unpatched software, or malicious actors.
Security vulnerability: Security vulnerabilities can be exploited by attackers to gain unauthorized access to a system, steal data, or launch attacks on other systems.
Service or daemon crashes: Services or daemons can crash for a variety of reasons, such as software bugs, resource exhaustion, or configuration errors, and can cause system crashes or unresponsiveness.
Software bug: Software bugs can cause a variety of problems, such as system crashes, data loss, or unexpected behavior.
SSH issue: SSH issues can cause problems such as difficulty in connecting, poor performance, or unexpected behavior. This can happen due to misconfigured SSH settings, network connectivity issues, or software bugs.
Swapping: When the system runs out of memory, data is moved from RAM to disk to free up space. This causes the system to become very slow.
System crashes: The kernel can crash for a variety of reasons, such as software bugs, resource exhaustion, or configuration errors, and can cause unresponsiveness.
Virtualization issue: Virtualization issues can cause problems such as poor performance, unexpected behavior, or difficulty in managing virtual machines. This can happen due to software bugs, hardware incompatibilities, or misconfigured virtualization settings.
