Once upon a time, it was conventional Unix server wisdom to reboot every month or so to make sure it was working correctly. These days many Linux system administrators boast about the number of days their servers have been up and running without interruption. BSD and other Unix-like OS users also claim similar uptimes, sometimes [...]
In the previous post, we covered a brief introduction to the magic SysRq key and dropped some hints about what it can do. In this post, we will actually learn how to perform one of the many functions it can be used to execute.
When your server becomes unresponsive, the first [...]
It could be a freeze, a crash, or simply completely or near unresponsiveness that drives you to shut off your server and start it back up cold. That, however, is never ideal. The ideal way to recover a system is to bring it back to complete functionality or simply restart it gracefully. Enter Magic SysRq, [...]
We are not quite done yet. Here are four more tips for boosting performance on Apache web servers.
1. Use mod_deflate/gzip – Gzip compression makes smaller file sizes for the content you send to client browsers. The browsers then uncompress and display through a seamless deflating process. The result is better server performance and faster [...]
It is inevitable that high traffic websites will cause a server stress. CPU and memory loads will rise, and it could affect performance. If you are not careful, it could even bring your server and all of its websites to a halt. Therefore, it is imperative that you have at least a general idea of [...]
CentOS is one of the most popular free and open source server operating systems. OpenVZ is a popular open source system for creating virtual private servers. Combine the two together, and you have a low-cost yet powerful VPS system. The following is a brief installation guide to get OpenVZ running on CentOS.
Step 1. Add [...]
If you are new to dedicated servers and have spent any time reading this site, you have undoubtedly come across posts from us reminding you to check and monitor your server’s log files. We even make sure to tell you where those log files are stored. In many cases, however, finding the log files is [...]
On most Linux dedicated servers, grub is the bootloader that gets the operating system loaded when the system first boots. With grub, you can determine which installed kernel version will load, attach any startup options to the kernel, and even load other operating systems. In most cases, grub will do its work silently never showing [...]
A process is any type of program currently running in a computer system’s memory. All types of dedicated servers have processes, and on Linux and Unix systems, they are easy to track, troubleshoot, and manage.
One of the most important commands you can use to track a process is “ps”. When executed it will display [...]
Your dedicated server needs regular maintenance. It will not take care of itself. The following checklist will help you keep your server in top shape.
1. Check your backups – Just because you make backups does not mean they actually work. You need to test them to make sure your server is performing backups correctly. [...]
Memory is one of the most important features of any server. The more RAM a program uses, the less you will have available for other applications. Therefore, it is important to monitor memory usage on your Linux server to ensure that all programs are playing nice and that nothing wrong is going on.
1. /proc/meminfo [...]
In the first part of this guide, we looked at some bash tricks that help you find things in the command history. In this section of the BASH (Born Again Shell) guide, we will look at some other functions.
Suffix command history
In the last post, we explained how to append the prefix from the previous command. [...]
Bash is the common shell environment used on Linux servers. If you manage a server, there is a good chance you will need to drop to the command line at some point and encounter Bash or one of its alternatives. The following are some basic commands that can help speed up your bash experience.
Reload [...]
Zombies present a particularly unique problem to system administrators. No, I do not mean the type of zombies that eat brains. I mean zombie processes. A zombie process is a process that is no longer active on a system but that refuses to die. In most cases, a zombie is not something that should alarm [...]
When your server suddenly stops functioning the way it is supposed to, there are a number of troubleshooting techniques you can try. One of the most important things you can do is backtrack and investigate to see if some changes you recently made might have caused the server to stop working. If you discover irreparable [...]
Once you delve into the world of Linux and Unix dedicated servers, you are likely to encounter the term NFS. What is it and how is it used in server configuration?
NFS stands for Network File System (NFS) and serves as a method for mounting drives or directories remotely over a network. NFS has [...]
When physical space is an issue but you have virtual space to spare, virtualization is a great way to consolidate multiple server instances into one machine. Linux is very flexible when it comes to virtualization and even has virtualization capabilities built into the kernel.
There are three levels of Linux virtualization that determine how the virtual [...]
Although it may sound like something out of a parenting handbook or a psychological journal, the term child process actually has nothing to do with human development. If you run a Unix or Linux dedicated server, you have likely encountered child processes without even knowing it. Therefore, it is good to know what child processes [...]
The word “hack” often brings up grim images of a shady individual sitting in a dark basement pounding away on a keyboard as he siphons money out of people’s bank accounts and funnels the funds to terrorist organizations. In reality, “hack” simply means a “solution to a problem” that is not necessarily uniform, standard, or [...]
One system resource that can quickly get away from you is memory. Every program needs memory, and some may take more than their fair share. Therefore, it is important to monitor memory usage to make sure your applications are behaving and also help you decide when it might be time to reallocate resources or even [...]
Often when we think of spam, it usually relates to incoming spam inundating mail servers and bogging down systems. Another way spam can harm your dedicated server is from the inside.
Many spammers do not setup their own servers or paid hosting accounts to send spam. They want to be anonymous. Therefore, they often use other [...]
On a Linux dedicated server, the shell provides a powerful arsenal of commands for you to manage your system. Used in isolation, these commands can be very effective. Used in combination, you can truly unlock the power of your system.
There are a few ways to string commands together. One of the most basic tools you [...]
On a Unix or Linux server, the “du” command provides a quick and easy method for finding out how much space each directory is using, as well as a summary of total disk usage. For example, if you just typed “du” from the command line, the output might look like this:
624 [...]
Another year has come and gone, and it is the perfect time for you to tighten up the screws on your server and make sure everything is in working order. The following checklist should help you along the way.
Run those updates – If you have been putting off updates, now is as good of a [...]
Spend enough time using Linux and you are bound to hear terms like “X Server”, “Xorg”, “X Windows”, or “X11″. All of these terms refer to the same technology, and none of them are things you need for your Linux-based dedicated server.
On Linux and Unix-like operating systems, the X Server is a layer that [...]
There are few ways to get a flame war going faster than to ask a Linux user which file system is the best? While many will argue in favor of one of the iterations of Ext: Ext2, Ext3, or Ext4, others will get more creative, promoting file systems such as ReiserFS, XFS, ZFS, [...]
On a dedicated server, managing users does not have to be a difficult affair. While the command-line tools are not overly complicated, you may at times want to use a graphical interface or run batch user operations. Webmin’s “Users and Groups” module may be exactly what you need.
You can find the Users and Groups module [...]
Most websites use databases to store the majority of their information. Therefore, backing up your databases is much more important than backing up other server files. Most other files can be replaced, but the information in your database is often unique and irreplaceable.
Where you store your database backups is very important and can ultimately decide [...]
IT managers have more options in managing their technology infrastructure than ever before. Hardware and software can be purchased, leased or even accessed on an as-needed basis. And software industry has evolved to the point that it can be either deployed on-site or accessed through third-party cloud services. Each of these options has their place.
As [...]
The Linux kernel is the foundation for a multitude of mobile, desktop, and server operating systems, from Android to Red Hat Enterprise Linux. Hardware drivers and other key components can either be built directly into the kernel and reside as modules that you can plug in or remove whenever necessary. What follows is a brief [...]
