DynaCache Cache Replication with WebSphere Process Server and ESB

As I blogged about previously, there is a useful technique which involves inserting Java components into SCA modules to cache the results of services using the DynaCache mechanism of WebSphere Application Server. See Gabriel Telerman’s excellent article for more information.

However, if you deploy applications using this technique across a WebSphere cluster, which is fairly typical of a production WebSphere environment, you’ll most likely want to look into WebSphere cache replication (using DRS – the data replication service). This means that rather than having an independent caches on each cluster member (i.e. each server), you’ll have caches that replicate data between each other when it is invalidated or updated in the cache.

This is documented in detail towards the bottom of this InfoCenter page, but broadly speaking you’ll want to modify the properties of the object cache you’re already using. In the article referenced above, the default cache services/cache/distributedmap is used, but to extend this with replication across a cluster, it’s probably appropriate to create your own object cache first if you haven’t already. You then need to specify a “replication domain” for that cache (you’ll need to create one if you don’t already have one), and the replication type. Often “Push only” is suitable for most performance requirements – this pushes new cache entries across the cluster when they are created, modified, or invalidated.

Some other points to be aware of:

  • The Data Replication Service doesn’t always start up straight away on server startup – sometimes it will take a few minutes.
  • It’s primarily intended for internal IBM use, but you may find that the tracing string com.ibm.ws.cache.*=all is useful for figuring out what’s going on inside the cache if it’s not behaving as you expect. It will show cache hits, misses, and replication.
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WebSphere Business Process Management v7 Production Topologies Draft Redbook Available

This post is a bit of a personal plug, but I’ve just returned from a Redbook Residency writing the book WebSphere Business Process Management (BPM) V7 Production Topologies Redbook, which illustrates how to set up various BPM products for production, including WebSphere Process Server. It’s a fully updated version of the previous book in the series, which was for V6.2 of the BPM products. The book is now available in draft, so please feel free to take a look – you can send feedback via the feedback e-mail address on that page. I’d also encourage you to rate the book, especially if you think it’s good!

WebSphere ESB / Integration Developer / Process Server 7.0 Announced

For those already working with WebSphere Integration Developer, WebSphere ESB, or WebSphere Process Server, or those considering using them, you might be interested to know that version 7.0 has just been announced and is scheduled to be available around the end of Q4 2009.

Please look at the official announcement for more information, but some of the new things I think are particularly interesting are:

  • Service Federation Management between WebSphere Services Registry and Repository and WebSphere ESB.
  • More pattern-based development.
  • Exploitation of WebSphere Application Server V7.
  • Improved Service Gateway scenario support.
  • Event sequencing support in WebSphere ESB.

Health Center with WebSphere ESB and Process Server

I attended a presentation last week by one of the developers of Health Center, a new monitoring and diagnostic tool IBM has made available for debugging Java Virtual Machines as they are executing. It’s available for any application that runs on an (IBM-based) JVM, but of particular interest to me is WebSphere ESB and Process Server.

I won’t repeat the installation instructions, which you can find here, but there are one or two gotchas you should be aware of:

  • At the time of writing, Java versions shipped with WebSphere ESB and Process Server (version 6.2.x) are sufficiently old that they don’t yet include the Health Center agent, so you will need to install this manually as described in the “Enabling an application for monitoring” link when you set up a connection in Health Center. Be careful to extract files into exactly the right directory.
  • I also suggest you then follow the instructions labelled “Configuring WAS to enable monitoring” in the Health Center Infocenter. If you are using the embedded Integrated Test Environment servers inside WebSphere Integration Developer, I suggest the topic “Configuring WAS test environment in RAD to enable monitoring”. Although the product names are different, the principles are essentially the same.
  • Be aware that (at the time of writing) Java 5 SR8 is used by WebSphere ESB and Process Server, so you’ll need to use the more complex form of JVM boot parameters as described in the help. This also means that it’s not yet recommended that use Health Center in production, although it will be useful in development, particularly when you’re focusing on performance, stability, or capacity issues. Hopefully this situation should change in later versions of WebSphere ESB and Process Server.

To give you a taster, once you’ve managed to connect, you’ll see some very cool screens, like this one that allows you to do trivial method profiling:

2009-07-21_160518

(sort by ‘Tree’ is particularly useful, as this includes time taken by methods that a given method has called).

Another handy view is this one, which allows you to watch your heap and JVM pause times over time (drag a box over a particular area to restrict all statistics to that period):

2009-07-21_160428

The best part of Health Center is that all data is updated in real time (and can be saved away and reloaded later), so you can (for example) watch your heap grow and shrink, your garbage collection happen, and so on. Overhead is generally minimal and since it uses a client/server architecture, is minimally invasive.

You can find out a lot more information on the Health Center website and the Java troubleshooting team’s blog.

Thanks to Toby Corbin for the original presentation and Dave Nice for assistance with Health Center.

David George Joins SOA Tips ‘n’ Tricks

I’m pleased to say that my colleague David George has agreed to join the SOA Tips ‘n’ Tricks team. He’s a WebSphere Process Server consultant, and will be blogging about it, WebSphere Integration Developer, and other related subjects. Like myself, David is part of IBM Software Services and works with IBM customers on a regular basis, so has a wealth of experience to share.

As always, please remember that the postings on this blog are our own and don’t necessarily represent IBM’s positions, strategies or opinions.

Automated Builds – Stopping BPEL Processes

I’ve recently been helping a customer put together an automated build and deployment for their Process Server artifacts, which include Integration Modules with BPEL processes. We used this excellent DeveloperWorks article as a basis, but we’ve extended it to also include automatic deployment – including uninstalling and reinstalling each module once it’s built. Anyone who’s tried to uninstall a module containing a running BPEL process without first stopping the process will know that this doesn’t work. So I was hunting around for an automated solution for this.

Luckily, there is one specified in the a documentation for WebSphere Process Server 6.0.2. For some reason, this seems to be missing from the 6.1 documentation, but the solution still seems to be valid. It works perfectly; this means a complete end-to-end automated deployment is possible.