Imagine you have an HPC cluster with a hundred compute nodes named node001-node100. The two commands below will help you generate a list of node names – either all name on one line or one name per …
Read the full story »Encoding Videos for XBox 360 and PS3
Both Xbox 360 and PS3 support a variety of video codecs and are capable of playing high-definition video files. One of the most popular formats for HD video files is Matroska (MKV), which provides excellent …
Sharing Videos from Linux to Xbox 360
Xbox 360 uses UPnP protocol to stream multimedia files from computers on your home network. Normally, you would have a Windows PC running WMP and sharing files. But what if you have a Linux box …
What’s the Best CMS
Content management systems are sprouting up like mushrooms after a warm April rain. If your job is to find the perfect CMS for your needs, you can spend weeks analyzing and comparing features of various …
Partitioning System Disk
When performing a new Unix OS installation you are usually presented with a choice of accepting the default partitioning layout or going into advanced settings and defining your own partitions. The default layout will normally …
Google Tips and Tricks
Google offers a remarkable set of powerful features. Unfortunately, most people are not aware of these possibilities. They use only the most basic functionality offered by Google and then waste their time on weeding out …
Convert Images to PDF
Converting sets of images into multi-page PDF files makes it easier to organize and share them. All you need for the conversion is the free that will run on your Windows, Linux, MacOS and many other operating systems. If you are running a recent version of Linux, chances are that ImageMagick is already installed on your computer (just type “which convert” to check).
Best of Web Design
As more Web surfers get high-speed access, Web designers are tempted to go overboard with multimedia sites that waste your time and distract you from the content. This little collection of Web designs is proof …
Random Filename Chooser
This is a rather peculiar little script with a purpose that may not be immediately apparent. The script will look for files in the specified folder; it will then pick one at random from the …
WordPress Quick Upgrade for Linux
Never ever upgrade WordPress to the latest version as soon as it comes out, unless you want to be the guinea pig dealing with the new bugs and incompatible plugins. Even if the new version …
Linksys WAP54G Secure Configuration
Below are some basic steps to secure a wireless access point (WAP). The screenshots are for Linksys WAP54G v. 3.04, however, the same steps will apply to wireless access points from other manufacturers. Understand this: …
Apache and Multiple Domains – from Home
Apparently there are folks out there who are still interested in running their own Web server from home. More than that – they want to have multiple domains. Guys, Web hosting these days is so …
Scali Manage (Platform Manager) CLI Guide
Scali Manage – the bloated and unpredictable HPC cluster management tool – has recently been acquired by Platform Computing Corp. It is to be integrated into Platform LSF and Platform OCS products. I can’t say …
Dealing With Disk Hogs
Some users and application developers believe that any free disk space on the server belongs to them. Suddenly you get an email alert saying that a server “xyz” ran out of disk space in /home. …
Useful SysAdmin Scripts: Search-and-Replace
Let’s say you moved your server to a new network and now it has a different IP address. You know your users have a habit of hard-coding the server’s IP into their scripts. So you …
Tips on dealing with the Bagle rootkit
Normally I don’t concern myself with Windows- related matters. However, the infamous Bagle rootkit and its numerous variations deserve some attention even from Unix sysadmins. Bagle annoyed me and my customers long enough. Essentially, Bagle …
Disaster Recovery Management
You business depends on your computers. Your employees need their databases, emails, files and applications to do their jobs. Imagine that you come to work on Monday and your database server is gone. How? It doesn’t matter. Let’s say it was transported out of your datacenter by the Romulans. Or, perhaps, the sprinkler system malfunctioned, flooded your datacenter and reduces your database server to a steaming, shorted out pile of junk.
Creating print.css for WordPress
Many WordPress theme designers choose to cut some corners with their creations. One of the more important things they skip over is print.css – the stylesheet that controls your blog’s appearance when you print it. …
Migrating email between hosted providers
Recently I ran into a small problem. A customer of mine was moving her site to a new hosting provider. Her old provider was Windows-based and her new provider was Linux-based. The old provider did …
Home Network Configuration Basics
Research shows that majority of everyday computer problems are caused by poor network configuration. That small white Ethernet cable plugged into the back of your PC is where most of your computer-related headaches are coming …
VxVM Recovery Cheatsheet for Solaris
This is a quick-and-dirty guide to recovering VxVM volumes and filesystems on a Solaris server. These instructions are not intended to be an in-depth troubleshooting guide for the Veritas Volume Manager. This is just something …
Improving WordPress Performance
WordPress is a great blogging engine and decent CMS. Unfortunately, most available WordPress themes- even those claiming to be “minimalist” – are bloated and slow to load. Heavy CSS stylesheets, multiple Java scripts, numerous graphics …
Use Perl inside Shell scripts
Perl is a far more powerful programming tool than any shell script. Sometimes you want to borrow some of that power without having to rewrite your entire shell script. There is an easy way to integrate Perl snippets inside your shell script.
Event Log »
Parallella: The $99 Linux supercomputer
Chip-company Adapteva announced on April 15th at the Linux Collaboration Summit in San Francisco, California, that they’ve built their first Parallella parallel-processing board for Linux supercomputing, and that they’ll be sending them to their 6,300 …
Xen becomes a Linux Foundation project
San Francisco, CA: In a surprising move, the Linux Foundation, the non-profit organization dedicated to Linux, announced on April 15th at the Linux Collaboration Summit that the Xen Project, the open-source hypervisor, is becoming a …
So you want to be a Unix sysadmin?
April 07, 2013, 10:41 PM — Thinking about becoming a Unix systems administrator?
The good, the bad, and the challenging
After several decades of administering Unix systems, I know more than I’d like to admit about …
Ubuntu 13.04 goes beta
It took a while, but the second, and final, beta of the next version of Canonical‘s Ubuntu Linux distribution, 13.04, aka Raring Ringtail, has been released.
Ubuntu 13.04 is only weeks away from release, but you can …
Why Windows fragmentation will blow Windows to smithereens (cough)
The Windows operating system has been plagued with fragmentation ever since the 3.x branch of the OS was released on multiple PCs. (Ahem)
Android fragmentation will blow up Android just as much as Windows fragmentation has …
Networking »
Fixing the mount.nfs: rpc.statd is not running Error
The rpc.statd service is used by NFS client to help it recover from loss of connectivity to the NFS server. When rpc.statd is not running, NFS is not able to handle remote file locking. You …
Red Hat: Changing Hostname and IP
Changing hostname and IP is frequently required when a server is being moved from testing or development to production. The process is a fairly simple one, but steps must be performed in a certain order to avoid complications.
Applications »
Install Pflogsumm PostFix Log Summarizer
Pflogsumm is yet another log analyzer/summarizer for Postfix. It is written in Perl and has been around for a while. Very simple to install, so I writing this post mostly as a note to myself. …
Installing Sendmail Analyzer on RHEL/CentOS
The Sendmail Analyzer can be useful for visualizing your Sendmail/Postfix log. The commands below can be copy-pasted as root on default installations of RHEL and CentOS 5/6 with default Postfix and httpd. If your configuration …
Data »
Filesystem Performance Testing Using dd
Below is a simple script to test filesystem read/write performance using dd with varying blocksize parameter. This can be useful for testing local filesystems as well as network-mounted filesystems. The end result will be a …
Quick BTRFS Test on OpenSuse 12.2
The recent announcement from Suse Enterprise Linux that Btrfs was production-ready raised some suspicions. The last time I tested btrfs (not very long ago) the primary issues were excessive CPU utilization and filesystem space that seemed to disappear into nowhere. So, as a quick test, I put together an OpenSuse 12.2 (3.4.6-2.10-desktop, OpenSuse 12.2) 64-bit VM (ESX) with one dual-core vCPUs, 4GB RAM, the OS disk and a 6GB striped LVM filesystem consisting of 4 4-GB virtual disks.
Monitoring »
openlava Quick Test
After years working with PBS and LSF, ran into Jeff Layton’s “Share the Load” review of openlava resource manager in the Feb 2013 issue of the Admin Magazine and nostalgia took over. So I built …
Filesystem Performance Testing Using dd
Below is a simple script to test filesystem read/write performance using dd with varying blocksize parameter. This can be useful for testing local filesystems as well as network-mounted filesystems. The end result will be a …
Commands & Shells »
Bash scripting: lists and random things
Imagine you have an HPC cluster with a hundred compute nodes named node001-node100. The two commands below will help you generate a list of node names – either all name on one line or one name per …
Fast IP Range Scanner in Bash
Just a simple script to scan an IP range and do a reverse DNS lookup. This can be useful for building an inventory of systems on your LAN. Just make sure to give your network …
Editor
Igor
Sr. Unix SysAdmin with fifteen years experience supporting Solaris, HP-UX, AIX, IRIX, and Linux servers in a large distributed environment.
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