Showing headlines posted by nemilar

When discussing the performance of a computer system, there are two concepts that are absolutely critical to understand, yet often get overlooked. These are latency – or, how long it takes for some operation to occur, and throughput – or, the amount achieved in a given time. Understanding these two concepts will help you diagnose and troubleshoot performance issues, and build a foundation of knowledge needed for more advanced concepts.

Your Central Processing Unit (“processor” or “CPU”) is at the very core of your computer; it’s the component responsible for all the number-crunching and math-doing that makes a computer go. As such, it’s important to be aware of some basic commands in Linux that let you query the hardware information regarding your processor. In this article, I’ll cover some of those commands, and how to read their output.

often find myself needing to run the same command on many boxes at the same time. For example, I’ll sometimes need to check the memory usage of a fleet of boxes. Other times, I’ll want to quickly grep the logs of multiple machines, for troubleshooting purposes. Once you grow beyond managing one or two servers, you’ll find yourself wasting a ton of time if you don’t have a way to run commands on multiple Linux computers simultaneously. In this post, I’ll explain how to quickly run commands on large numbers of Linux machines at once.

I occasionally find myself waiting several hours for a process to complete; sometimes it’s just a very lengthy ‘make’ command, but it more often some benchmark program that needs to run for a while before generating any useful results. I got tired of being chained to my computer while these things run, so I wrote a small python script that executes an arbitrary command and text me the status when it completes. This article will show you how to use my script, in the hopes that others will also find it useful.

In Linux, the 'free' command is used to show memory usage; but the information presented is more complex than just 'used' and 'free'. This article explains what the additional fields mean, and shows you how to determine your system's actual memory usage.

Previously we discussed what swap devices do, and whether they're necessary in modern machines. This article explains how to manage swap devices, files, and swap priorities.

Easily benchmark your network connection between Linux boxes by using the netcat tool - you'll get reliable results in just a few seconds.

What does a swap device do? And do I actually need to have one on my Linux machine? This article explains the use of swap devices, and when they're necessary.

By now, everyone knows that if you want to make a file unrecoverable, you can't simply delete it - you have to use a tool like 'shred' or 'srm' to overwrite its contents. But a common question is whether this is effective on an ext3, ext4, or other journaled filesystems. This article discusses these filesystems, and whether secure deletion tools work on them.

In Linux, there are two types of file links: hardlinks and softlinks. This article shows the difference between hard and soft links, how they work, and explains when you should pick a softlink over a hardlink.

This tutorial shows you how to setup an interplanetary background in Linux, including live-updates for current cloud coverage and daylight! Set an image of Earth, Mars, the Moon, or the entire solar system as your background, and have it update every hour with a cron job. Very cool!

Most Linux users are familiar with cron, which is used to schedule tasks to run at a given time. However, most people don't use cron except to setup system tasks, because it's not the most friendly program to use. Enter gnome-schedule, an easy way to schedule tasks using a GUI. This tutorial will show you how to schedule tasks using the Gnome Scheduler, a graphical front-end for cron.

This how-to will teach you two commands, iftop and nethogs, that you can use to monitor network traffic on a Linux machine. You can use iftop to view traffic by individual connection, port, network segment, or remote host, which gives you a detailed accounting of all packets coming in and out of your machine. Nethogs is a great program as well, and lets you know which processes are using bandwidth on your computer.

Most Linux users are familiar with the top command. Top shows you a list of processes on your system and provides a ton of useful information such as their CPU usage and owner. Unfortunately, this isn’t always enough data and many people don’t know where to turn next. This article covers three performance monitoring applications that show information top doesn’t tell you, and can greatly help in troubleshooting bottlenecks or just finding out more about your system. These utilities are iftop, iotop, and pv.

Maverick Meerkat, the version of Ubuntu slated to be released later this year, brings with it several features and improvements that the Linux community has been eagerly looking forward to. I’ve taken a look at the blueprints for this next release, and picked out a few of the major items that Linux end-users will be interested in. Here are 5 things to look forward to in Ubuntu 10.10.

While we all have our own reasons for liking Linux and open source, here are my top five (and a half!) reasons why, as a power user, I prefer to use Linux. You’ll notice that these reasons are quite a bit different from why I think Ubuntu makes a great operating system for Mom, which just goes to show how versatile Linux can be.

This tutorial will show you how to add a secure-delete option to the contextual menu in Ubuntu and Fedora Linux. We all know that when you simply delete a file, it’s possible to recover it later. Sometimes this is useful, if you accidentally delete something important; but usually this is a problem, and you really want that file gone forever. Additionally, this tutorial can be adapted to add any command to the Nautilus context menu.

Canonical’s foray into the tablet arena is fundamentally different from both the iPad and a WebOS tablet, and unfortunately reeks of a company failing to learn from their competitors successes and failures. Here are four reasons why an Ubuntu tablet simply won’t work.

Linux does many things differently than Windows, and users new to Linux are sometimes confused and frustrated because the Windows systems they are used to don't apply to the Linux world. Here are five things that all Linux users should know to help ease the transition between operating systems.

One of the most frustrating problems a network administrator can come across is an IP address conflict, when two or more machines on a network try to use the same IP. It's frustrating because it's a difficult problem to detect and resolve -- unless you know the right tools.