My latest article has been published in issue 21 of the Microsoft Architecture Journal:

EDA: SOA Through The Looking Glass

Please leave questions and comments here.

My article on “employing the domain model pattern” has been published in the August edition of MSDN Magazine.

Here’s a short excerpt:

“In this article, we’ll go through the reasons to (and not to) employ the domain model pattern, the benefits it brings, as well as provide some practical tips on keeping the overall solution as simple as possible.”

Continue reading…

I’ve made the cover of the latest issue of MSDN magazine.

OK, enough of that.

I really am thrilled that Microsoft has taken a non-technological article and promoted it in such a way. Change is happening, and I like it.

With a name as long as most of my variables, this article is quite the failure-fest:

Build Scalable Systems That Handle Failure Without Losing Data

No drag and drop, no wizards, code completion, or anything.

Real world problems with no magic solutions. A real analysis of message loss over HTTP, what additional problems durable messaging brings with it, how integrated systems can lose consistency as the result of database deadlocks, and more.

The solutions described are first and foremost about thought processes – knowing the nature of the problem, how to design a solution that addresses it, and what new problems now need to be dealt with. You’ll see exception management strategies (no, you shouldn’t be try-catching), how that feeds into deserialization exceptions, error queues, and finally into a versioning strategy that also addresses the human element. There’s a lot of architectural meat. I had to cut out a lot of filler in order to get it all into the 7 page limit.

If you haven’t yet read the book Release It! this article might be considered the Cliff Notes version. But you still should read the book. It really is worth your time.

Comments and questions are most welcome.

Spectacular Scalability with Smart Service Contracts

In this article, I attempt to debunk some of the myths around stateless-ness as the key to scalability.

Here’s how it starts:

It was a sunny day in June 2005 and our spirits were high as we watched the new ordering system we’d worked on for the past 2 years go live in our production environment. Our partners began sending us orders and our monitoring system showed us that everything looked good. After an hour or so, our COO sent out an email to our strategic partners letting them know that they should send their orders to the new system. 5 minutes later, one server went down. A minute after that, 2 more went down. Partners started calling in. We knew that we wouldn’t be seeing any of that sun for a while.

The system that was supposed to increase the profitability of orders from strategic partners crumbled. The then seething COO emailed the strategic partners again, this time to ask them to return to the old system. The weird thing was that although we had servers to spare, just a few orders from a strategic customer could bring a server to its knees. The system could scale to large numbers of regular partners, but couldn’t handle even a few strategic partners.

This is the story of what we did wrong, what we did to fix it, and how it all worked out.

Continue reading…

The industry’s first IT architecture skills library has been unveiled by the International Association of Software Architects (IASA), a 5,000-member association focused on defining and supporting the professional duties of IT architects. Consisting of more than 600 pages of information, the library is an invaluable resource for each primary skill of the practicing IT architect.

A collaborative effort of 75 practicing architects from around the world and commissioned by Microsoft, the library can be accessed for free at: www.IASAhome.org/web/home/skillset
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My part in this effort was an article called “Fear those Tiers”, for the topic of Solutions Architecture – here’s a teaser:

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I was horrified. My beautiful tiered architecture was buckling under the stress tests – at one tenth of the expected load of the system. And this was quality hardware, not the regular junk we scrapped together in most test labs, after all, this was the company’s flagship project. And I began seeing my once-bright career flashing before my eyes. The only redeeming thing about this situation was that I had learned the hard way to do performance tests early in the project, and that there might still be enough time to save the situation. A couple months later things were back on track but I’ll never forget the feeling I had back then – “All the big vendors are pushing this exact architecture. How could this be happening?” Since then, I’ve learned that tiers and networks are not to be taken lightly in any architecture and this article chronicles my journey, and how I got to a robust and scalable architecture.

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Read the full article here.

Just as a side note, the connection between DDD and SOA was discussed in a session I hosted at Cortina this year where we found that workflow was the glue that connected the two.

How to select an Object Relational Mapping tool for .net (http://www.developer.com/design/article.php/3531871).

The name is misleading – I don’t talk about a single tool, but rather the way O/R mapping fits (or doesn’t fit) into various architectural styles. BTW, the name comes from the coming How-To-Select(TM) Guide where a diet version of the article will appear as an Informed Opinion.