Keep an eye out for ZooKeeper

Wow, I love the simplicity that ZooKeeper brings to a really hard set of distributed problems. Check out this Introductory Video that explains it more in depth. Basically group leadership/coordination and cluster wide configuration issues are taken care of if you Use ZooKeeper.

Oh and it's an Apache Project now. Yay! Seems like the project website is still not fully setup since they are migrating from SourceForge to Apache, be here's a link to the source tree.

TODO: Double Write Buffers

Note to self: investigate implementing the Double Write Buffers idea in ActiveMQ. ActiveMQ keeps several indexes into the persistent messages that it's holding and when ActiveMQ is shutdown ungracefully, we rebuild the indexes from the data logs due to them being in inconsistent state. If your queueing up millions of messages, building those indexes can take a long time.

Double buffering may allow us fix inconistencies in those index and gets us running faster..

ActiveMQ/SpecJMS/Camel Webinar

Whoa, time flies by, and I forgot to post about the upcoming webinar that I will be co-hosting with Rob Davies on June 10th. We will be covering some messaging basics, introducing Apache ActiveMQ and Apache Camel to the audience, but most interesting I think will be the section where Rob will be covering the results that IONA has been seeing benchmarking ActiveMQ against the SpecJMS2007 test suite. I totally agree with Rob's comment that "An independent benchmark is important, because it negates the chance to skew home groan tests to a vendor's strengths."

InfoQ Covers ActiveMQ 5.1 Release

InfoQ has posted nice article on the new features in the ActiveMQ 5.1 release versus the last 4.1 release:

Apache ActiveMQ, an open source provider of enterprise messaging services, recently released version 5.1 which includes improvements in stability and performance of the message broker product. This version also includes support for priority message ordering and a Microsoft Message Queue (MSMQ) to ActiveMQ Bridge with the new msmq transport component.

There are also improvements in the monitoring module of ActiveMQ container. A new DestinationSource class was added to access the available Queues or Topics or listen to Queues/Topics being created or deleted in the container. There is a new API to help end users view available destinations and query them to find JMS statistics such as active queue count, queue depth, number of messages etc.

Read More...

ActiveMQ 5.1.0 Release

For all of you who ran into issues with ActiveMQ 5.0.0 when running it in anger, I highly recommend you give the just released ActiveMQ 5.1.0 a try. This release focused focused on making the broker rock solid. It resolved several bugs which only reared their heads in high load situations. Memory leaks have been squashed and performance has even improved in several areas.

Even if you have not had seen any issues with your 5.0.0 installation, I'd highly recommend you upgrade to 5.1.0 to avoid running into some of the bugs that have been addressed in the release.

Mulitcast not working on a Linux box?

Just ran into a problem where some mutlicast tests were failing on a linux box and I could not figure out why. Did a little bit of research and found out that you may need to add a route for it first. So if you have this problem try running:

route add 224.0.0.0 netmask 240.0.0.0 dev eth0

or if you have an older version of linux like me:

route add -net 224.0.0.0 netmask 240.0.0.0 dev eth0

More ActiveMQ Fanfare

Nice to see the new year starting off right. I Noticed this post over at the eaimatrix.com:

A plethora of message queuing products exist in today's EAI market, all aimed at providing solutions to the problem of application integration. Few can however lay as much claim to fame as ActiveMQ, an open source Message Broker and JMS/Enterprise Integration Patterns provider which is licensed, developed and distributed under the open source Apache emblem. ActiveMQ provides support for Cross Language Client and Protocols as well as a powerful messaging broker which is supported in Java, C, C++, C#, Ruby, Perl, Python, PHP.

Read the full article by Ade Ayonrinde.

ActiveMQ Webinar

Late notice.. but James and I are doing an ActiveMQ Webinar in an hour and half. Sign up for it and let us know what you thought about it.