Monitoring Performance in Linux

1. top – Display Linux Tasks

This is a very used tool by any Linux administrator because it provides real-time information about the running tasks, system and about the tasks which are managed by the kernel.

top

More examples about how to use the “top” utility can be found here: http://www.cyberciti.biz/faq/tag/top-command/

2. vmstat – Report Virtual Memory Statistics

The command “vmstat” provides very useful statistics that relates to: CPU activity, virtual memory, kernel threads, IO blocks, kernel threads, processes, etc.  For more examples about how to use vmstat, you can read: http://www.cyberciti.biz/faq/tag/vmstat-command/

vmstat

3. lsof – List Open Files

The full name of this command is self-explanatory. Basically, the “lsof” command helps a sysadmin to find the open files and the processes that keeps them opened.  You can read more about it here: http://www.catonmat.net/blog/unix-utilities-lsof/

lsof

4. tcpdump – Dump Traffic On a Network

This tool is a network packet analyzer and a sniffer that can be used to capture the packets transferred through a specific network interface. A detailed tutorial can be found here: http://www.danielmiessler.com/study/tcpdump/

tcpdump

5. netstat – Network Statistics

When you want to use “netstat” it means that you’re looking for information about the inbound/outbound in terms of interface statistics. Many of us already know it from Windows. More useful practical examples using netstat can be found here: http://www.cyberciti.biz/tips/tag/netstat

netstat

6. iostat – IO Statistics

The name of this tool is also self-explanatory. It is designed to provide statistics about the input/output of different storage devices and it also provide info about the CPU status. Some useful examples on how to use this tool can be found here: http://linux.101hacks.com/unix/iostat/

iostat

In order to make this tool available, you have to install the sysstat package from the repository.