Essential guide to Linux in the enterprise
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Red Hat Enterprise Linux offers many graphical tools that make managing a Red Hat server easy, even if you don't...
have experience with the command line. A good place to begin is to learn how to set up PuTTY and Xming and start graphical programs from your server. In this tip, you'll learn how to use the command gnome-system-monitor to monitor and manage processes on your server.
Everything your server is doing is happening as a process. For example, if you start up an Apache Web server it runs different processes. In some cases, these processes can't do what they're supposed to do. When that happens, process monitoring and management becomes important.
The graphical tool to monitor and manage processes is the Gnome System Monitor. If you run a full graphical desktop, you can find it in Applications > System > System Monitor. If you want to start it over a remote connection, such as a PuTTY/Xming connection you can start the tool by running the gnome-system-monitorcommand. If you aren’t able to start this program, use yum -y install gnome-system-monitor to install it on your server.
Gnome System Monitor offers a convenient way to manage processes
The most important tab on Gnome System Monitor is the Processes tab. Here you'll find a list of processes, in which the most active process is listed on top. You can decide for yourself how the processes are sorted: Click on the %CPU column header to sort the processes by CPU activity, or click on Memory to sort them by memory usage.
Specify how processes are selected by clicking on the column headerM
If a process is causing you trouble, you can find all relevant management task by right-clicking the process. You might want to do that if a process gets stuck and you need to terminate it or if a process is eating up all available CPU cycles and you need to calm it down. By right-clicking any process on the list, you'll access the common process management tasks. These five are the most relevant:
- Stop Process: This pauses a process. Use this if you temporarily want to make more system resources available for other tasks to run smoothly.
- Continue: Use this after stopping a process when you want to continue running it.
- End Process: Use this option to end a process in a gentle way. The process gets a signal to stop its work and has time to close open files, save files and stop the process after it has completed the work.
- Kill Process: In case a process can't be stopped using End Process, you may want to force it off. Use this process if you want to terminate the selected process, no matter what. Be aware that by using this option, no files will be closed with saves, and you are likely to lose data.
- Change Priority: By default, all processes will get an equal share of system time. In some cases, your process might not get enough system time. If that happens, you can change its priority, or it's nice value. After selecting this option, a slider appears to set the new nice value. Slide it to the left to increase the priority (it will show a negative nice value), or slide it to the right to decrease priority.
Adjust the process priority by using the slider to increase or decrease its nice value.
The Process Management tab is by far the most important tab in gnome-system-monitor, but it's not the only tab. More useful information can be found on the Resource tab, which shows performance graphs of your system, or the File Systems tab where you can get an overview of the amount of disk space that is still available on your server’s file systems.
The gnome-system-monitor tool offers all you need to manage processes on a Red Hat server. You can use it to get an impression of the current load that processes are causing on your server as well as to stop processes or adjust their priority.
ABOUT THE AUTHOR: Sander van Vugt is an author and independent technical trainer, specializing in Linux since 1994. He is also a technical consultant for high-availability clustering and performance optimization as well as an expert on SLED 10 administration.