Sunday, October 5

Litmus Test for Metadirectory vs. Virtual Directory

No, I don't want to re-open a debate. Just floating someone else's idea...

I already mentioned some of the things I overheard at DIDW 2008 and the panel titled Lessons From Successful Virtual Directory Deployments. I was looking at my notes today and wanted to float an idea that one of the panelists offered (I think it was Divya Sundaram of Motorola). He said (paraphrased):
If you front-end data (or a data store) that you don't own (or don't have control of), then you need to replicate/sync data (instead of virtualizing the view).
Is that a good general litmus test for the Metadirectory vs. Virtual Directory debate?

As I've said numerous times, I can think of clear use-cases for both scenarios. But this might be a good general rule of thumb. BTW - the panel seemed to unanymously agree that both capabilties are useful and should be part of the toolbox.

1 comment:

Matt Pollicove said...


I'm sure you're surprised that I chose to comment on this issue.

Back in the MaXware days, I think we would refer to this as an aspect of the "Political" arguement.

The fact is, as we all know, there are going to be those data-center managers who do not want anyone messing with their data directly. If I, as a manager, do not want the IdM folks to tinker with the data, I would have to decide between the two methods. It all comes down to the question of: How sensitive is the data? If it's not sensitive, sure, let them have a copy, I know my "authoritiative" copy is still pure. If there's sensitive aspects to it, or I need to control its spread, then I'd ask for it to be virtualized.

Like all aspects to the virtual/meta debate, I could twist Mr. Sundaram's statement right around to make a case for virtualization. I don't know that it qualifies as a litmus test. I don't know that there can be any one statetment that decides if data should be virtualized or not. It would have to be a complete flow chart to discuss all of the possibilities (response time, sensitivity needs, privacy needs, use cases, etc)