Scalent Systems

SOA without SOI = SOL

Tuesday, September 26, 2006

There's been a lot of discussion over the past 12-24 months about Service Oriented Architecture (SOA).

SOA is one of those really great ideas that doesn't take into account the laws of physics. Much like AOL deciding in the late 1990's that it'd open up modem banks (promptly flooding their network), SOA creates a host of challenges for the underlying physical infrastructure, which in turn demands SOI - a Services Oriented Infrastructure.

Why is this so? To understand the challenge created, it's necessary to first consider the way SOA works.

With SOA, various business services publish their interfaces, which can then be arbitrarily used by other services. So, for example, if I have a server running a transaction processing app, I can send transactions "at" that server (from various other servers in my network) and assume that I'll get my transactions processes / get a confirmation message.

But since there's no hard link established between SOA elements - at any time, anyone in the network can start using that published transaction server - predicting load on the published SOA elements is almost an NP-complex problem. At any time, load on any element may be large or small. You may need one, small server running your transaction processor... or you may need fifty quad-cpu machines with a load balancer in front.

My contention, therefore, is that you need an SOI to complement your SOA - a way of creating and scaling up (or down) new server systems (or entire multi-tier application deployments) in near real-time, to match the needs of your SOA.

So in an ideal world, as SOA needs rose, your SOI would be turning on new servers, creating load-balancers and SOA server elements, linking in the appropriate LANs and storage networks, and scaling the system.

This vision - SOI - is what Scalent provides.

And what happens if you have an SOA without SOI, you may ask?

Well, in that case, you're just SOL*.

*("So Out-of Luck"... or something like that).

posted by Scalent Systems at 1:43 PM

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