Top 5 tops: keep tabs on your system

Anyone who has spent any time at the command line has probably encountered the venerable top command. It’s an excellent system administration tool that make efficient use of the limited UI facilities available for command line applications.

mtop - MySQL terminal based query monitor

mtop monitors a MySQL server, showing the queries which are taking the longest to complete. But it doesn’t stop there. The tool also displays the cache hit rate, the number of open tables, the number of queries per second your server is handling, and other vital database statistics.

apachetop - realtime Apache monitoring tool

ApacheTop is a tool for monitoring the traffic on your web server in real-time. If you’ve ever run tail -f /var/log/apache2/access.log, then this program is for you. Once installed, you can specify which logfile apachetop should monitor with the -f argument.

The output shows how long the program has been running, the time of your site’s last “hit,” and the average request rate (since the tool started, and for the past 30 seconds). It also displays the top urls, referrers, or hosts in a top-like list. You can toggle between the three list modes by pressing ‘d’. Press ‘h’ while the program is running to view other runtime options.

iftop - displays bandwidth usage information on an network interface

iftop monitors bandwidth utilization on a network interface. The tool displays a table of current bandwidth usage by pairs of hosts - source and destination. By default iftop shows the amount of traffic, and the name of the hosts that are sending and receiving traffic. But you can toggle between different display modes by pressing ‘t’. Pressing ‘p’ will display which port traffic is running through. Again, pressing ‘h’ while the program is running will display additional runtime options.

atop - monitor system resources and process activity

atop is top on steroids. It shows system-level counters for cpu-, memory-, and swap-utilization (like top), but also shows disk I/O and network utilization counters. You can use atop to monitor system-wide resource utilization, or limit the output to display accumulated resource utilization for a particular user or program. The list of active processes can be sorted by CPU activity (’C'), memory consumption (’M'), disk activity (’D'), or network activity (’N').

htop - interactive processes viewer

htop is another interactive process monitor (like atop, and top). It’s a command line application, but it’s much more visual than other similar utilities. You can add a variety of “meters” to the display that summarize system statistics like uptime, load average, CPU-, memory-, and swap-utilization, and more. If colors on the command line hurt your eyes, you can make htop “monochromatic” by pressing F2 and selecting “Colors.”

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• Linux