Yesterday I've been talking about RHQ at the Swiss Java Users Group in Zürich. This was a good session with around 50 people.
While Zürich is not far away from Stuttgart, it took me nevertheless some time to get there. With the current issues around ICE wheels, the train wasn't able to go as fast as desired and we arrived 25mins later than expected -- luckily I've taken one train earlier anyway.
View over the shoulder of the train driver when leaving Stuttgart main station
Rheinfall in Schaffhausen as seen from the train
When you look at the date, it was 11/11 which is also start of the so called 5th season, carnival. So at the main station, there were already groups of Guggen-music playing in their costumes. Later on I saw them throughout the city at various places. It's great fun to listen to them, as they are full of energy. Even as they are playing the same instruments as the boring (German only?) brass bands, it is not the same at all.
Guggen music in Zürich main station
I went to my hotel (Limmathof, close to the main station), checked in, deposited my bag and then strolled around a bit. When I wanted to take the tram to the Technopark I had to find out that the ticket dispenser only accept swiss coins. So I had find an ATM, get some swiss money (I am no longer really used to get some other currency when traveling in Europe, as I never make it to UK and in so many other countries, the Euro is happily accepted). After I had to buy something as the note to coin exchanging machine did not accept 50 SFr notes. But after all I succeeded. So if you go there, make sure to get at least 10SFr in coins as soon as possible.
The talks in the Technopark were held in a room called "Fortran" - how strange for Java related talks :) When setting up the Laptop I had to find out that the German Schuko plug would not fit the existing outlets. Luckily someone had an adapter and we found an outlet that accepted this adapter.
In my talk I was first showing some slides about what RHQ is, where it comes from, how it relates to Jopr and JBoss ON, then showing some bits about resources and the subsystems. Then I was demoing the live application. I wanted to show that monitoring the thermometer chip would also be possible, but this failed at the demo (later I found out, that libusb was missing in my agents lib/ directory. When I added it to the running agent and did a restart of the plugin container, it worked like a charm).
After this demo, I briefly showed the bits about plugin development. Unfortunately one can show and tell sooooo much around RHQ and Jopr that the time was already up.
I think my talk was well received, I saw some people taking notes and also had people asking questions and making suggestions. I guess I will get some more feedback from the organizers, as they've distributed some feedback forms for the attendees to fill in.
Next after my talk and a short break, Bela Ban was giving a talk about how to tune a web application that is clustered and that uses JGroups and JBossCache for replication purposes. Bela first presented some baseline figures and then tweaked replication of the session versus attributes, buddy replication versus total replication and also replication on access of getters versus setters. Bela was also showing some architectural set ups for clusters that have been proven to work well.
End of story was that with some tweaking and possibly some small application code changes one can gain a big lot of performance.
Bela was also talking about the new mod_cluster from JBoss. If you haven't heard about it, check out its web page. Basically mod_cluster tries to solve the configuration issues that exist around mod_jk. Configuration of mod_cluster is done on the JBossWeb side where nodes announce themselves to the frontend httpds. Also the JBossWeb instances can send their load information to the apaches who react upon it. The computation of the load is pluggable.
Another cool thing is that JBosWeb can tell the apaches that a web application is going down, so the apaches know no longer to serve this node.
After the talk we had an apéro in a room called "Pascal", where I also met with Thomas and Galder from the Neuchâtel office. Unfortunately Fady did not make it as well and Thomas directly had to leave afterwards again.
After the apéro, Bela, Galder, Silvano from the Jugs and I went to an Italian restaurant (Il Gallo at Escher-Wyss-Platz) where we had some good discussions and good food too.
After I have dropped my laptop off at the hotel, I strolled around the city some more - really great. This morning I took the ICE back to Stuttgart and am now back at my desk :) Here are some more impressions of Zürich.
Polybahn as seen from my hotel window
Zürich and Limmat river by night
Vending machine that not only dispenses sweets, but also fuses(!)
Arrival of the ICE in Zürich for my way back to Stuttgart