FOSDEM 2011

It's been great again. Over 5000 Open Source developers and enthousiasts meeting to share more than 200 hours of knowledge over the course of a weekend at FOSDEM 2011, held at campus Solbosch of ULB in Brussels, Belgium.
Last year I went there for the first time, for just one day, and I liked it so much I immediately decided to go back this year, but for the whole two days.

So there I was, on Saturday afternoon, after taking two trains, a metro and a bus, entering the ULB campus where FOSDEM is held, seeing the signs pointing to all different buildings and rooms where talks were held, the catering trucks, and a busy bunch of enthousiastic people.

I headed for the MySQL & Friends devroom, where I met some of the people of the phpMyAdmin team, which I joined last year. I hadn't met them before, so this was a nice opportunity.
These are some of the talks I attended on Saturday :

• What's new in MySQL 5.5
• Data Recovery for MySQL
• flashrom: Run your BIOS/EFI/firmware updates under any free OS
• 0MQ: Multithreading magic 
• Seeks Project: let's take back websearch
• Multimaster MySQL failover
• Multi-Master Replication Approaches

After this, we had a phpMyAdmin team dinner and afterwards I introduced them to  some fine Belgian beers.

Sunday was a bit chaotic, I hadn't planned to see that much talks, one of the talks I planned to attend was canceled, and I missed another one, because I left early to catch the canceled one (but I didn't know it at that time), but I still went to some :

• The difficulty of forking 
• Can we build a simple, cross-distribution installation framework?
• Cold boot attacks on RAM readout 
• Really fast x86 boot
• Building a free, massively scalable cloud computing platform
• How kernel development goes wrong and why you should be a part of it anyway 

After the last talk, it was time to go home. A special FOSDEM bus brought us back to the railway station, were I had some dinner before I headed home.
It was a nice weekend, with a nice Open atmosphere, again perfectly organized by and for the community.  In case you missed it, this was FOSDEM 2011 (a video artists impression).

I'm looking forward to next edition already!

Debian 6 (Squeeze) is released.

A few days ago, Debian 6.0, codename Squeeze, was released after a 2 year development period.

Of course this new release contains a lot of new stuff : lots of new and upgraded packages, faster booting because processes are started in parallel (if dependencies allow it), integration of grub2, volatile repository is replaced by squeeze-updates, ...

Because I want to use Tomcat 6 on a production server, I wanted to try the upgrade on a testbox. Everything went quite smoothly. All steps for upgrading from Debian 5.0 (Lenny) are clearly explained in the release notes (Chapter 4). The only thing that went wrong, in my case was the update of mysql-server. For some reason it was uninstalled, but the replacement package for the new version 5.1 was not installed.

After the upgrade process, I rebooted and I noticed grub 0.97 (now called grub-legacy) was still used, but it transfered the bootprocess to grub2. This worked like a charm, so then I ran  (as root) :

# upgrade-from-grub-legacy

to install grub2 in the MBR and boot from it. Rebooting went perfectly afterwards.

So far I'm quite pleased with squeeze and the upgrade process. I'll do the upgrade with my other boxes in the next few days.

XFS check

I wanted to check the consistency of the data partition on one of my servers. It is 6.5TB and formatted with XFS, so I ran :

#xfs_check /dev/sdb1

And I got :

xfs_check: out of memory

After some searching, it turns out that a lot of memory is needed to perform the xfs_check on a large file system : >6GB and you need to run it on 64bit, to able to address that memory.

My system is a 32-bit with only 4GB, so I would probably not be able to run xfs_check on my system, but there is another way :

#xfs_repair -n /dev/sdb1

This tools tries to repair a XFS filesystem, but with the -n switch no changes are written to the file system, so the effect is quite the same. It still uses a lot of memory if you have a lot of files/inodes on the file system, but 3GB on a 32-bit system should be sufficient.

Of course, if xfs_repair finds a problem, you can still run it without the -n switch, to repair the filesystem.

All time favorites : games

I've recently rediscovered the wonderful pass time of gaming. And I was thinking of a few great games I played in the past, in alphabetical order :

• Assassin's Creed II
• Exile (Myst III)
• Grim Fandango
• Riven, the sequel to Myst

They earned a position in this list because of the mere of beauty of the game, which was usually a combination of graphics, music, scenery, atmosphere and gameplay.

Happy 2011!

Happy New Year!

May 2011 be a year of friendship, love, joy and happiness, good health and prosperity!

2010

A lot of things happened in 2010. I'm not going to write an exhaustive list, but will just mention things that spring to mind.
On a technological level : I got my new server and installed linux on it, I learned to use vim and git, and started contributing to the Open Source community by joining the phpMyAdmin development team. I visited FOSDEM for the first time and will certainly do so this year.
On a professional level : I created a new website for my department using Drupal, and installed a new backup server.

One of my resolutions for 2010 was to read more, and I achieved this. If possible I read a chapter every evening, and I hope to continue doing this in the new year.
I also spent quite some time playing games, watching films and series and (re)discovered some music. Some of the highlights of the year : Assissin's Creed II, the best game I played in years; Isbells and Mumford & Sons, the latter doing some great gigs; and 1984, classic by George Orwell. :)

And I met a lot of interesting people, made new friends and got to know some people better.

Resolutions 2011

Bit a more of the same of last year. I made some progress, but there is always room for improvement :

• Smile (even) more!
• Enjoy more and worry less
• Continue reading
• Be more confident
• Look for a new place to live

Cleanup apt cache

Over time, the cache of apt, the Debian package installation application, keeps growing. Every time a package is installed or updated, the original packages is stored in the cache. After a few months of updates, the cache grows quite big, because nothing is deleted from it automatically.
Keeping the original packages from all software you have installed is certainly a good idea, but the packages that are replaced by newer ones are kept as well.

The cache can be cleaned. using this command :

apt-get autoclean

This removes all unneeded (old) package files from the apt cache.

If you want to clear the cache completely, and thus removing all packages, use this command :

apt-get clean

Both commands are quite safe to use, because they only remove the downloaded packages from the apt cache. The installed files naturally remain untouched.
This way you can sometimes free a few hundred megabytes after a few months.

Ubuntu is based on the Debian packaging system, so this applies to every flavor of Ubuntu as well.

Firefox plugin : HTTPS Everywhere

Yet another Firefox plugin to be added to the list of useful plugins : HTTPS Everywhere.

Essentialy, this plugin forces your browser to use the secure (encrypted) https protocol when visiting certain websites (like Facebook, Google, ...). This way, no data is sent in cleartext over the internet. When visiting these websites, everything is encrypted by your browser before it leaves your computer, and is then decrypted by the server (and vice versa, when the server sends the webpage back to your PC).

Why would you want this?

If you login over a normal http connection, your username and password are sent over the internet, for everybody who can intercept that package to read. The same with sensitive data that might be visible on websites your are visiting.

You are probably wondering who can catch your packets? To do that you must most certainly be an internet wizard? Not true. Recently a Firefox plugin was published, called Firesheep, that allows a computer to look around on your local (wireless) network, and hijack Facebook and other sessions on social networking websites and actually see what they are seeing.
For instance, when you are using a free wireless accesspoint, someone with the firesheep plugin, can easily watch what you are doing. (With more sophisticated software this is also - and was already - possible, but this requires more skill)

So, to protect yourself from these kind of attacks, it's better to use the https protocol as much as possible. And a nice tool to help you do this is, is a plugin like HTTPS Everywhere, or Force TLS. The Force TLS plugin does about the same as HTTPS Everywhere, but is more difficult to setup, because you have to tell the plugin for which website you want to use https. Downside of the HTTPS Everywhere plugin, is that it only works for the preprogrammed websites.