Linux Basic Maintenance Commands

Background:

SONIC (Software for Open Networking in the Cloud) is an open-source network operating system widely used in data center and cloud environments. As a Linux-based network operating system, SONIC relies on the Linux kernel and underlying system tools to achieve high-performance network packet processing and device management. However, troubleshooting in network environments is a common challenge, especially when dealing with complex network topology, high traffic loads, or hardware issues.

To ensure the stable operation of the SONIC system, administrators need to master some basic Linux maintenance commands. These commands can help administrators monitor system resource usage (such as CPU, memory, disk, and network interfaces), identify potential performance bottlenecks, and quickly locate and resolve network faults. For example, abnormal traffic on network interfaces, CPU overload, or disk I/O bottlenecks can lead to network packet loss or latency, affecting the overall performance of the network.

Disk

In the SONIC system, log files, configuration files, and databases can consume significant disk space. To monitor disk usage on file systems, preventing issues such as system logs failing to write or configuration files being lost due to insufficient disk space.

To quickly determine if disk space is sufficient, especially when dealing with large log files or databases. Shows in a human-readable format (e.g., KB, MB, GB):

df -h   or    df -lh

 To confirm whether storage devices are correctly mounted in the SONIC system, particularly when troubleshooting storage-related issues, use this command:

lsblk

which can list specific information of all hard drives and partitions, and judge whether some hard drives are abnormal.

To verify if the file system on storage devices is correctly configured, avoiding storage failures caused by file system issues, use:

lsblk -f

to check the current usage of each partition, ensure all disk storage spaces are enough.

To monitors the load on system I/O devices. In the SONIC system, high disk I/O can lead to delays in network packet processing, identify disk I/O bottlenecks, use this command:

iostat

Memory

The SONIC system consumes significant memory when processing large volumes of network packets. Use this command to monitor memory usage and prevent performance degradation due to insufficient memory:

free -h

CPU

To displays CPU architecture information, such as model, number of cores, number of threads, frequency, etc, use this command:

lscpu

In the SONIC system, certain processes may consume excessive CPU resources, causing delays in network packet processing. Use this command to display real-time system resource usage, including CPU utilization, process information, etc:
top

In the SONIC system, CPU overload can lead to network packet loss or latency. Use this command:

mpstat

to monitor CPU usage and ensure efficient network packet processing.

If user wants to refresh utilization statistics for each CPU core in different time, use this command:

mpstat -P ALL 1 (refreshes every 1 second)

To display overall system performance information, including CPU, memory, and I/O statistics

vmstat 1 1: Refreshes every 1 second

which helps administrators quickly identify system performance bottlenecks, especially under high traffic loads.

In the SONIC system, high load can cause delays in network packet processing. To display system uptime, number of users, and load averages (1-minute, 5-minute, and 15-minute averages), use this command:

uptime