Basic commands for Linux OS Performance Monitoring

Monitoring the system performance regularly is very much important to ensure the services are being delivered to the end customers without any latency. OS Performance monitoring is an important layer of the entire system performance, along with other layers including application performance, network performance etc…

OS Performance monitoring tools are used for monitoring, visualising, storing, and analysing system-level performance measurements. It allows the monitoring and management of real-time data, and logging and retrieval of historical data.

Red Hat Enterprise Linux provides several tools that can be used from the command line to monitor a system performance.

We are discussing here some of the built-in command line tools for system monitoring.


The top program provides a dynamic real-time view of a running system.  It can display system summary information as well as a list of processes or threads currently being managed by the Linux kernel.

Top command helps the system administrator to find the process and users who utilize more resource in the system.

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Let’s see the example below.

top is provided by the procps-ng package. It gives a dynamic view of the processes in a running system. It displays a variety of information, including a system summary and a list of tasks currently being managed by the Linux kernel


It is the abbreviation of “process status”. ps displays information about a selection of the active processes. The output of ps command may vary depends on the parameters we used with it.

Let’s see the example below

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ps is provided by the procps-ng package. It captures a snapshot of a select group of active processes. By default, the examined group is limited to processes that are owned by the current user and associated with the terminal where the ps command is executed.


It is the abbreviation of virtual memory statistics. vmstat reports information about processes, memory, paging, block IO, traps, disks and cpu activity.

Let’s see the example below

Virtual memory statistics (vmstat) is provided by the procps-ng package. If we use vmstat as a command with no parameters, it will show you the report  which contains the averages for each of the statistics since the last reboot.


It is the abbreviation of System activity reporter.  It collects and reports information about system activity that has occurred so far on the current day.

sar is provided by the sysstat package.  It can be used to monitor Linux system’s resources like CPU usage, Memory utilization, I/O devices consumption, Network monitoring, Disk usage, process and thread allocation and more.

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Let’s see the example below

sar command will show only cpu monitoring activity if any flag is not specifies by user. It displays result on the output screen by default , in addition the result can also be stored in the file specified using  -o filename option.


It is the abbreviation of network statistics. Netstat prints information about the Linux networking subsystem. Print network connections, routing tables, interface statistics, masquerade connections, and multicast memberships.

netstat is provided by the package net-tools .By default, netstat displays a list of open sockets.  If you don’t specify any address families, then the active sockets of all configured address families will be printed.

Below example shows how netstat can be used to print the routing table.


It is the abbreviation of input/output  statistics .The iostat command is used for monitoring system input/output device loading by observing the time the devices are active in relation to their average transfer rates.

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Let’s see the example below

iostat is provided by the package sysstat.The iostat command generates reports that can be used to change system configuration to better balance the input/output load between physical disks.

That’s some of the very basic and important commands and it’s usage. Hope it will help you to monitor your system effectively. We will discuss more performance related topics in upcoming posts.

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