Commands and Tools for Monitoring Linux Performance

1.top: Linux process monitoring

The top command under Linux is a performance monitoring program. Many system administrators often use it to monitor Linux performance. This command is available in many Linux or Unix-like operating systems. The top command is used to display all running and active real-time processes in a certain order, and the display results are updated regularly. This command displays CPU usage, memory usage, swap memory usage, cache usage, buffer usage, process PID, commands used, and others. It can also show the memory and CPU usage of running processes. For system administrators, the top imperative is a very useful tool to monitor the system and take corrective action when needed. Common usage of the command format is:

# top

2. VmStat : Virtual Memory Statistics

Linux's VmStat command is used to display statistics about virtual memory, kernel threads, disks, system processes, I/O blocks, interrupts, CPU activity, and more. By default, the vmstat command is not available on Linux systems, you need to install a sysstat package that includes the vmstat program. The common usage of the command format is:

# vmstat

3.Lsof: List open files

In many Linux or Unix-like systems, there is the lsof command, which is often used to display all open files and processes in the form of a list. Open files include disk files, network sockets, pipes, devices, and processes. One of the main situations in which this command is used is when the disk cannot be mounted and an error message is displayed that a file is being used or opened. With this command you can easily see which file is being used. The most common format of this command is as follows:

# lsof

4.Tcpdump : network packet analyzer

Tcpdump is one of the most widely used network packet analyzers or packet monitoring programs, which is used to capture or filter TCP/IP packets received or transmitted on specified interfaces on the network. It also has an option to save captured packets to a file for later analysis. On almost all major Linux distributions, tcpdump is available. # tcpdump -i eth0tcpdump: verbose output suppressed, use -v or -vv for

full protocol decode listening on eth0, link-type EN10MB (Ethernet), capture size 96

bytes

A command-line tool for network packet and network interface statistics. It is a very useful tool that system administrators can use to monitor network performance, locate and troubleshoot network-related problems.

# netstat -a | moreActive Internet connections (servers and established)

6. Htop: Linux process monitoring

Htop is a very advanced interactive real-time Linux process monitoring tool. It is very similar to the top command, but it has richer features, such as user-friendly management of processes, shortcut keys, vertical and horizontal display of processes, and more. Htop is a third-party tool, it is not included in the linux system, you need to use the YUM package management tool to install it.

# htop

7.Iotop : Monitor Linux disk I/O

The Iotop command is also very similar to the top command and the Htop program, but it has the ability to monitor and display real-time disk I/O and process statistics. This tool is very useful when looking for specific processes and processes that make heavy use of disk reads and writes.


8. Iostat: Input/Output Statistics

Iostat is a simple tool for collecting statistics showing the input and output status of system storage devices. This tool is often used to track performance issues with storage devices, including devices, local disks, and remote disks such as using NFS.

# iostat

9.IPTraf: Real-time LAN IP monitoring

IPTraf is an open source real-time network (LAN) monitoring application that runs on the Linux console. It collects a lot of information, such as monitoring of IP traffic through the network, including TCP flags, ICMP details, TCP/UDP traffic separation, TCP connection packets and byte counts. It also collects common and detailed information about interface status: TCP, UDP, IP, ICMP, non-IP, IP checksum errors, interface activity, etc. 9. IPTraf - real-time LAN IP monitoring

IPTraf is an open source real-time network (LAN) monitoring application that runs on a Linux console. It collects a lot of information, such as monitoring of IP traffic through the network, including TCP flags, ICMP details, TCP/UDP traffic separation, TCP connection packets and byte counts. It also collects common and detailed information about interface status: TCP, UDP, IP, ICMP, non-IP, IP checksum errors, interface activity, etc.

10. psacct or acct: monitor user activity

psacct or acct tool is used to monitor the activity of each user in the system. These two service processes run in the background, they closely monitor all the activities of each user running on the system, and also monitor the resources used by these activities.
System administrators can use these two tools to track the activities of each user, such as what users are doing, what commands they submitted, how many resources they are using, how long they have been on the system, and so on.

11.Monit: Linux process and service monitoring tool

Monit is a free and open source software and a web-based process monitoring tool. It can automatically monitor and manage system processes, programs, files, folders, permissions, sum verification codes and file systems.
This software can monitor services like Apache, MySQL, Mail, FTP, ProFTP, Nginx, SSH. You can check the system status through the command line or the network interface provided by this software.

12.NetHogs: Monitor the network bandwidth used by each process

NetHogs is a small open source program (similar to the top command under Linux) that closely monitors the network activity of each process on the system. It also tracks the real-time network bandwidth used by each program or application.

13.iftop: Monitor Network Bandwidth

iftop is another open source system monitoring application that runs in the console. It displays a list of application network bandwidth usage (source host or destination host) over the network interface on the system. This list is updated regularly. . iftop is used to monitor network usage while 'top' is used to monitor CPU usage. iftop is a member of the 'top' family of tools that monitors selected interfaces and displays the current network bandwidth usage between two hosts.

14 Monitorix: System and Network Monitoring

Monitorix is ​​a free lightweight application tool designed to run and monitor Linux/Unix server systems and resources. It has an HTTP web server that regularly collects system and network information and displays it graphically. It monitors system load averages and usage, memory allocation, disk health, system services, network ports, mail statistics (Sendmail, Postfix, Dovecot, etc.), MySQL statistics, and more. It is used to monitor the overall performance of the system to help identify errors, bottlenecks and unusual activity.

15. Arpwatch: Ethernet Activity Monitor

Arpwatch is designed to monitor Ethernet address resolution (MAC and IP address changes) on Linux. He continuously monitors Ethernet activity over a period of time and outputs a log of changes in IP and MAC address pairings. It can also send email notifications to administrators, warning of changes to address pairings. This is useful for detecting ARP attacks on the network.

16. Suricata: Network Security Monitoring

Suricata is an open source high-performance network security, intrusion detection and anti-monitoring tool that can run on Linux, FreeBSD and Windows. Developed and copyrighted by the non-profit OISF (Open Information Security Foundation).

17. VnStat PHP: Network Traffic Monitoring

VnStat PHP is a web-based front-end rendering of the popular network tool "vnstat". VnStat PHP presents network usage in a beautiful graphical interface. It can display upload and download traffic in hours, days, and months and output summary reports.

18. Nagios: Network/Server Monitoring

Nagios is the leading and powerful open source monitoring system that allows network/system administrators to spot and fix problems before they affect normal business. With Nagios systems, administrators can remotely detect Linux, Windows, switches, routers and printers within a single window. It can warn of danger and point out if the system/server is abnormal, which can indirectly help you to take rescue measures before the problem occurs.