Installing Flash player browser plugin in 64-bit Ubuntu 11.04

I got a new hard drive for my laptop and decided to make a leap of faith and move to 64-bit version of Ubuntu, since I had to install a fresh system anyway. In case you didn’t know – Adobe doesn’t have stable Flash player version for 64-bit Linux. Adobe Labs offer preview release codenamed …

Increasing Ruby interpreter performance by adjusting garbage collector settings

According to Evan Weaver from Twitter it is possible for a typical production Rails app on Ruby 1.8 to recover 20% to 40% of user CPU by simply adjusting Ruby garbage collector settings. In August I set out on a quest to verify that statement on HeiaHeia servers. Results have really exceeded my expectations. Time to execute application tests locally decreased by 46%. On production servers CPU utilisation decreased by almost 40%.

Call to undefined function: imagecreatefromjpeg()

While installing new Joomla modules I came across this PHP error (yep, still have to deal with PHP occasionally). I had PHP compiled from source on Ubuntu 10.04 as per earlier instructions. Quick check of phpinfo() indicated that while gd module was compiled in, it didn’t have JPEG support: GD Support enabled GD Version bundled …

Running Rails applications using Nginx with Passenger on Ubuntu Server

If you’re planning to run Rails applications on Nginx using Phusion Passenger, and do it on Ubuntu Linux, here’s what needs to be done.

Even though there’s Ubuntu nginx package available (which works perfectly when you’re running PHP apps using FCGI), if you want to take into use Phusion Passenger, you’ll need to recompile Nginx from sources.

Instructions below were verified on Ubuntu 10.04 (Lucid Lynx) Server Edition.

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Moving Joomla, WordPress and other PHP/FastCGI apps to Nginx

Have you moved your site from Apache to Nginx and now your FastCGI (php-cgi/spawn-fcgi) processes die/hang/crash periodically and your users see “HTTP 502 Bad gateway” or “HTTP 504 Gateway timeout” instead of a website?

I have faced this problem and found a relatively simple and robust solution. Here’s how I did it on Ubuntu 9.10 (Karmic Koala) and 10.04 (Lucid Lynx) server edition.

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Setting up your own git server on Ubuntu

This will create a new user ‘gitosis’ and prepare a structure for repositories in /srv/gitosis. Now let’s initialize a gitosis-admin repo – it is used for managing repositories and access

Of course there’s always an option to use github. And if you’re working on an open source project, or want to concentrate on coding and not system administration, github is a lot better option than setting up and managing your own git server (I’ve been so impressed by @defunkt‘s presentation on #frozenrails, that started recommending github to everyone 🙂 But if you already pay for a virtual machine somewhere (like Linode), then setting up your own git server might be a viable option, especially that it is sooo easy.

The following instructions have been verified on Ubuntu 10.04 Lucid Lynx, but should work at least on Ubuntu 9.04 and 9.10 just as well.

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Informal notes from #frozenrails 2010

Thanks to organisers from Kisko Labs and the HHLinuxClub on Friday, May 7th, 2010 Finland got its first  Rails conference.

Conference has drawn very interesting speakers and  international crowd – from Finland (naturally), Sweden, Poland, Germany, Russia and other countries. I made a few notes from selected talks on the conference.

Chris Wanstrath / GitHub (@defunkt)

  • Slides: http://www.slideshare.net/err/inside-github
  • Linus Trovalds Google tech talk about git – where Linus tell you that you’re stpid if you’re not using git
  • rack-mobile-detect – is used by GitHub, super useful if you’re planning to create mobile optimized version
  • GitHub uses Unicorn as an application server – personally I’m not sure if that’s better than Apache + Passenger. Chris tells that Unicorn is cool, because does fair load balancing on Linux kernel level, also Rails are loaded only once – and then required number of processes are forked – and this is very fast, a lot faster than loading rails separately for each Mongrel. And when one of the processes dies – there’s no need to re-load Rails, but just fork another process.
  • GitHub users BERT to forward requests to one of their six servers – BERT to Erlang is the same as JSON to JavaScript
  • GitHub doesn’t use delayed_job anymore since they needed several queues with different priorities – so far they use resque, but are considering developing a real queue management system

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No space left on device – running out of Inodes

One of our development servers went down today. Problems started with deployment script that claimed that claimed “No space left on device”, although partition was not nearly full. If you ever run into such trouble – most likely you have too many small or 0-sized files on your disk, and while you have enough disk space, you have exhausted all available Inodes. Below is the solution for this problem.

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