After five years spent as a CIO, I have developed the following conviction:
 Major architecture re-engineering projects are fuelled by pain (one could say : no pain, no gain :)).
Enterprise Architecture (EA) projects (I should rather say programs, as in a family of projects) require an unusual amount of effort and alignment throughout a long period of time. The alignment is even more difficult to achieve than the sustained level of effort, especially with a large IT organization. Alignment here means the fact that a large group of people decide to make sub-optimal choices, from their own viewpoint, to achieve a larger-scope goal. It may be strange way to look at alignment but it makes sense: if the logical choice for each actor was to move towards the same direction, there would be nothing to talk about :)
Introducing an EA scheme (what we French call "urbaniser" the information system) usually occurs because a blazing limitation of the IS has been found. It is too slow, not flexible or agile enough, not reliable enough and, most often, too expensive, etc. The level of pain is necessary to break through a "decision/action" threshold, since there are obvious risks. From a technology perspective, an EA relies on an integration infrastructure (ESB, EAI, ETL, and so on). From a culture perspective, new concepts and a new vocabulary are introduced.
What happens if the program is successful? After a while (it could be a long while :)) the pain recedes. As a consequence the alignment starts to weaken. This is not simply an internal/organizational issue for the IT department. Deploying an EA approach is a corporate endeavour, which requires from all business division a common wish to build a global system. The alignment here means that each division is ready to relinquish some of its interests for the common good.
Because of this weakening of the common resolve, the master plan becomes too heavy to carry and one returns to (some of) the previous faulty behaviors that caused the pain in the first place… I have been thinking about this for the last three years and I have come to build a second conviction:
 Service Oriented Architecture is the sustainable approach to develop a "well-architectured" information system over time.
This statement probably sounds lame and dull to anyone familiar with the SOA (Service Oriented Architecture) concept. All possible "claims to fame" have already been made when SOA is concerned :). I should first state a few caveat:
- I do not mean SOA as a technical architecture framework (Web Services, ESB, …) but as a governance method for building reusable information system assets. I do not want to dwell on this today, I'll come back to it some other time (one may look at the discussion about the SOBA acronym to grasp this ambiguity).
- I do not mean a unique, shared, common architecture. As I explained in my first book, I am a strong believer in diversity. Actually, one of the first papers to talk about "sustainable enterprise architecture", from Marten Schoenherr and Stephan Aier, precisely considered sustainability a benefit of a distributed approach. I refer my customary readers to page 98 of my book where I also develop this idea (e.g., the main benefit of SOA compared to earlier approach, such as EAI, is the ability to decentralize the EA program).
- I really push the analogy with "sustainable development" to the core: a sustainable EA approach is one that produced benefits without requiring so many efforts from the culture, the people, the organization that it stops whenever the actors have the freedom to do so. This is really about people, and especially the relationship between business process owners and their IT providers.
- I am discussing about a large-scale enterprise and its information system as a whole. I consider the problem of "SOA at a departmental scale" solved (this is illustrated by the existence of so many successful implementations …). The sustainable alignment of a medium-size information system is not such a formidable task :)
Hopefully my second book will be available soon to English-speaking readers (since I have finished the translation). They will see that one of my central theme is that a "well designed IS" is a corporate responsibility, not something that may be left to the CIO. The CIO may take the leadership for a "special re-engineering" program/effort, but this cannot last. Eventually it is a matter of management culture (unless the CIO wants to become a "dictator" but he or she usually gets fired quickly if this temptation is too strong :)).
Pierre Bonnet recently opened a web site about this very topic: http://www.sustainableitarchitecture.com/home. His book about the same topic will be out next month. The web site is really interesting, together with the companion site about the Praxeme method. If you go and read through it (which I encourage you to do :)), you may think that it develops a similar line of ideas (obviously, with more details and more thought-though principles). I actually agree with everything … but I do not think that it reflects truly what sustainable development is really about: people. I am personally a big fan of the ACMS approach (Agility Chain Management System). Unfortunately, (or fortunately, since no so many people may understand what it :)), this is not where I see the issue for deploying a SOA Enterprise Architecture in a sustainable way. There (rightfully so) a lot of talk about SOA governance nowadays. Unfortunately it remains complex and abstract, whereas the issue is the appropriation from all stakeholders in the company. I will return to this topic in further postings, since I believe that this (SOA governance) is the key to agility. I fear for those who will promise agility from the sole technical merits of a SOA architecture.
It turns out that there is a totally different meaning for "sustainable IT architecture" ! If one looks at the electric consumption of a data center, it is raising dangerously over the years (with respect to the double issue of energy price increase and greenhouse gas emissions). Electric consumption here includes both the powering of the computers and their cooling. Both tend to be proportional to the square of the processor frequency (one way to look at it, although the resistance decreases with the smaller scale designs). Both tend equally to be proportional to the amount of computation that is made, which is clearly growing fast in most companies.
This is why Google is seeing energy consumption as a key issue. For instance, read this newspaper article to find out about Urs Hoelzle approach to reduce server electricity footprint (more technically-savvy readers may look at this :)). Since then, Hoelzle has said Google is looking into neutralizing its carbon emissions by the end of the year.
The link with architecture is as follows. The simplest way to increase the computing power without increasing the consumption is to use massive parallelism. I don't have time to go into details today. One may look at the StorageMojo web site to get a lot of interesting stuff.
I have just finished Ray Kurzweil book "the Singularity is near" (2005). As usual, this is a fascinating book, especially from this "sustainable development of IT" perspective. From a general perspective, it is a refreshing view from a "technology optimist" which offers a clear break from the prophets of doom. As far as computing is concerned, Kay Rurzweil offers hope for software designers to be able to use much, much faster hardware (although, if you read the book, you'll see that the name may no longer be appropriate :)), something that I am dreaming off each time I run of my "game theory simulation" :)
Ray Kurzweil's optimism does not cancel the validity of Google concerns (different time scale). One might say, then, that a sustainable architecture needs to run on a grid-like structure (or any other form of massively parallel system architecture).