How to solve CentOS system failure

There are many ways to solve CentOS system failures. Here are some common steps and tips:

1. Check the log file

• /var/log/messages : System log, containing various system events.
• /var/log/secure : Security-related logs, such as SSH login attempts.
• /var/log/httpd/error_log : If you use the Apache server, there will be an error message here.

2. Use diagnostic tools

• dmesg : Displays the contents of the kernel ring buffer, which helps understand hardware and driver issues.
• journalctl : View systemd logs, suitable for CentOS 7 and above.
• top/htop : Real-time monitoring of system resource usage.
• vmstat : Report virtual memory statistics.
• iostat : Displays the usage of CPU and I/O devices.

3. Troubleshooting of network problems

• ping : Test network connectivity.
• netstat : View network connections, routing tables, interface statistics, etc.
• ss : Similar to netstat, but more efficient.
• ifconfig or ip addr : Check the network interface configuration.

4. File system check

• df -h : Check disk space usage.
• **du -sh * **: Recursively view directory size.
• fsck : Check and fix file system errors (note: it is safer to run in single-user mode).

5. Service management

• systemctl status [service_name] : Check service status.
• systemctl start/stop/restart [service_name] : manage services.
• chkconfig : Sets the service startup level.

6. Package Management

• yum update : Update all packages.
• yum remove [package_name] : Uninstall the package.
• yum install [package_name] : Install the software package.

7. Hardware detection

• Use smartctl to check the health of the hard drive.
• To check memory usage, you can use **memtest86 ** for memory testing.

8. System recovery

• If the problem is serious, consider using rescue mode or Live CD/USB for system recovery.
• Back up important data before performing operations.

9. Seek help

• Search online for relevant error information and find solutions.
• Visit the official CentOS forum or community.
• Ask for help from experienced colleagues or friends.

10. Preventive measures

• Regularly back up the system and data.
• Keep the system and software up to date.
• Monitor system performance and promptly discover and solve problems.

Things to note

• Be sure to back up important data before making any major changes.
• Don't delete or modify system files at will unless you fully understand their functions.
• If you are not sure how to do it, it is best to consult a professional first.

Through the above steps, you should be able to diagnose and resolve most CentOS system failures. If the problem persists, it is recommended to study the relevant logs and documents in depth, or seek professional technical support.

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