Lenz Grimmer's blog

Vorab ein Disclaimer: nein, ich bin nicht auf der Suche nach einen neuen Job

Ich habe auf der FrOSCon am letzten Wochenende Lukas Chaplin endlich mal persönlich getroffen, nachdem wir schon seit längerem in Online-Kontakt standen. Er betreibt das Job-Portal Linux Lancers (powered by MySQL), auf dem Stellenanzeigen mit dem Schwerpunkt auf Unix-, Linux- und Open Source-Jobs veröffentlicht werden. Dieses Jahr waren sie auf der FrOSCon als Gold-Sponsor und Aussteller vertreten und hatten wohl immer viel zu tun.

Ich finde diese Idee sehr gut – es zeigt, daß die Arbeit an und mit Open Source Software durchaus keine brotlose Kunst ist und Know-How in vielen Bereichen dringend gesucht wird. Mir ist bisher kein weiteres Portal mit diesem Fokus bekannt. Eine Suche nach "MySQL" liefert viele Hits, quer über die Republik verteilt. Kenntnisse und Erfahrung mit Opensource-Technologien zahlen sich aus! Die Website ist noch in einer frühen Betaphase, aber das machen die Inhalte wieder wett. Laut Lukas ist ein Relaunch des Portals in Arbeit, bei dem sowohl die Suchlogik als auch die Darstellung der Suchergebnisse überarbeitet wird.

With OpenSQL Camp and FrOSCon being over for almost a week now, it's time to come up with a short summary. I traveled home on Monday morning and then took Tuesday off, so I had some catching up to do...

As for the past years, FrOSCon rocked again! According to the closing keynote, they had around 1.500 (unique) visitors and I had a great time there. I really enjoyed meeting all the old and new faces of the various Open Source communities. The lineup of speakers was excellent, Jon "maddog" Hall's keynote about "Free and Open Source Software in the Developing World" was quite insightful and inspiring.

Most of the time I was busy with speaking at and running the OpenSQL Camp session track in room "HS6", but I managed to sneak out and listen to a few other talks as well. Additionally, I gave a presentation about ZFS on Linux, which had a good crowd and some interesting discussions.

This year, all of the sessions in the main lecture halls were streamed live, so people not able to attend could at least get a glimpse on what was going on these two days. Many times it was a really tough decision to make – there were way too many good sessions going in parallel. So being able to see the recording afterwards somewhat relieved that pain. The FrOSCon team has already begun to publish the video files – they are separated by day and lecture room and can be obtained from http://froscon.tv/.

And we were really lucky with the weather, too - the weekend was warm and sunny, a perfect setting for the social event, which is one of the highlights of FrOSCon. Impressive: this year, the attendees consumed one cubic meter (1000 liters) of Beer!

Finally, I'd like to express my special gratitude to all the speakers of OpenSQL Camp – thank you very much for your support and for devoting your time to participate in our subconference! It was appreciated.

I tend to switch between Linux and OpenSolaris as my desktop operating system from time to time. To be more flexible in this setup, I store most of my work-related data (e.g. source trees, VirtualBox images) on an external 320GB USB disk drive, using the ZFS file system. While OpenSolaris supports ZFS natively, I can access the file system on Linux using zfs-fuse and I could even mount these file systems on a FreeBSD system, if needed. There aren't that many file systems that allow an easy exchange of data between (Open)Solaris and Linux – the other ones that I am aware of are FAT and UFS, which both don't give me the confidence and flexibility I need.

A while ago, I purchased a second external drive of the same size and now use both of them in a mirrored configuration. This gives me several benefits:

• Redundancy: external disk drives have a higher risk of getting physically damaged, so having a mirrored copy of my data ensures that I won't lose anything important if one of the drives dies.
• Increased performance: ZFS is capable of distributing reads across both devices, thus I get twice the speed of a single USB 2.0 port, if I connect the drives to ports attached to separate USB host controllers.
• Automatic resyncing: When I'm on the road, I only take one half of the mirror with me. In case this drive gets lost/stolen, I still have a second copy of the data at home. ZFS complains about the pool being in degraded state, but continues to work normally. When I return home, I simply attach the second drive again and ZFS automatically resyncs (resilvers) anything that has been modified in the meanwhile.
• I can use snapshots for backup purposes. I have a small Intel Atom based PC (running OpenSolaris) that acts as my central file server (using two 1TB disks in a ZFS mirror) and CUPS print server. If I want to create a backup of my external USB disks, I create ZFS snapshots of the file systems in question and transfer these to the home server using "zfs send/receive". This works both locally by connecting the drives to the server box directly or via SSH over the network. I wrote a small shell script to automate this process. The transfer is done in an incremental fashion – only the differences between the current and the last snapshot are being propagated. To save disk space on the external drives, I usually discard all older snapshots except for the last one or two. On the file server, I maintain snapshots for a longer time period. The snapshots are named by using a simple date/time timestamp (filesystem@YYYY-MM-DD-HH:MM), this makes it easy to go back to a particular snapshot in case I'm looking for something I may have removed by accident, but I still recall when it was last used.

From my experience, ZFS is a very solid and reliable solution, providing impressive functionality with a very user-friendly UI (you only need use two commands, zfs and zpool).

If you want to learn more about ZFS and how to use it in practice, consider attending my upcoming talk (in German) about this subject at FrOSCon 2010 in Sankt Augustin, Germany!