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How to ask for help for Linux issues.

All of us need a little help now and again. Linux users aren’t any different than MS-Windows or Mac users in that regard. The difference is that to get help for Linux, you need to do a little more research first.

We’ll assume you don’t have a nearby Linux knowledgeable friend that knows everything. You’ll need to ask people you do not know for help. Or, perhaps you are the Linux guru in your circle of friends and your questions are more complex than most.

Below, I’ll suggest a few methods to use to get help and outline the data you should include in your requests to optimize the ability of others to actually be helpful to you.

Today a friend sent an email with a Gnome helper app to setup a panel so remote ssh logins could be added to the Gnome Panel. There are lots of applications, or applets, like this out there. They all read and edit config files and provide a GUI to do something that has been possible for years and years. I guess if you are new, then having a program that edits configuration files before you’ve learned to use a UNIX editor is a good thing. Noob-friendly editing is good and reduces the perceived learning curve for Linux. Long-time users know that having a program to edit simple configuration files isn’t needed. You can edit them yourself and accomplish amazing things.

Some background reading on X/Windows. Here’s an architecture image as a reminder:

Recall that the X-Server runs on the desktop and that the X-client runs on the other, sometimes remote, machine sending requests for to the specific screen to be displayed. Also, you can run many X-servers on a single machine, even if they are not physically displayed.

Nothing is New

Do a google search on “fvwm screenshots” to see what I mean. This one or one very similar has been displayed as long as I can recall using fvwm. fvwm has been around since before I started using UNIX/Linux in 1993. I didn’t find it until 1995 when it was a pioneer in virtual desktop capable window managers. At that time, people were still using wmw and twm, yes, people actually used twm. When you first started using FVWM, you wanted to configure the menu for your local needs. It was easy to get going quick and setup remote logins to other systems for everything, including telnet, ssh, email, web browsing, editing files, running desktop word processors … whatever. Today the GUI settings are still maintained inside text files and these can be customized manually. Sometimes there are a few more steps since GUI programmers today like to take a simple concept and turn it into an environment that requires many, many more config files. Still, manually adding menu items to a panel for Gnome, KDE, XFCE, or LXDE is relatively easy.

This Cyberciti.biz article explains settings and techniques to increase the default RAID re-build performance from 4k to 51k in his example. The key settings were

1. Increase the speed limit max by adding dev.raid.speed_limit_max = 500000 to /etc/sysctl.conf
2. Enable bitmaps during the rebuild and disable them after
   1. sudo mdadm —grow —bitmap=internal /dev/md0
   2. sudo mdadm —grow —bitmap=none /dev/md0

Cron has been around since the beginning of UNIX systems. It is a scheduler that will run programs or scripts periodically when scheduled. The scheduling can be for a specific time annually or at the same minute every hour or any period between those. The hardest part for me is recalling the specific format of the crontab. It is very specific and any mistake will

Different effective user accounts use different crontab files, so you can run periodic jobs as yourself or some other account like root. More crontab info .

Ok, finally, on to the tips.

In the last few days, a permanent article here about a WiFi Router Security Checklist has gotten a very large number of hits, over 100x the normal page views. It contains 15 or so suggestions that every home or small business wifi router user should do from a security point of view.

When you see these messages, what does that mean to you?

I’ve been slightly disappointed with overall VirtualBox performance and decided to see what I could do to make things faster. For me, there are 3 elements to the performance issue. CPU, Disk and Network I/O. At this point, I only have possible solutions for two of the three areas.

My server is running Ubuntu Server x64 10.04 with VirtualBox 3.1.6 OSE directly from the Ubuntu repository. Below, I’ll describe how to improve both disk and network I/O performance. I think these suggestions will apply to other versions and MS-Windows hosts too.

Lucid locked up on me today. The external disk array was really busy running multiple transcoding jobs at the time – love the quad core CPUs!. Those jobs filled up /raid, not any important file systems and locked up X/Windows. HOME is on a different FS too, BTW.

Installation of VirtualBox OSE (Open Source Edition) using the Ubuntu repositories should be easy. For me, there were a few issues that I figure other people may run into. I was able to solve them.

The Matroska container format for video has become popular over the last few years because it merges a number of good ideas and let’s a single file contain multiple video, audio and subtitle streams. No longer do you have to keep multiple .vob/.mpg/.avi.mp4, and multiple .sub/.srt/.idx files to have 3 different audio and subtitles. All of them can be placed into a single .mkv file. For me having the subtitles efficiently contained inside the same file is good, but the real, fantastic reason that MKV containers are brilliant is you can easily correct aspect ratio issues without re-encoding.

Here’s another article for why you should also use MKV if you’d like more specifics.

There’s another nice bonus. In my testing, the .mkv files are always smaller than the .avi files from which they are made.

Jumping into the How-To