Identity Matters

A few months ago Volker Scheuber from Novell started a bit of a twirl when he blogged about why he doesn't really like virtualization and virtual directories. Volker is a well respected guy in Identity Management, and he's been with Novell for many years. He is intrinsically involved with their Dir-XML meta-directory product. In the old days, meta-directories used to be the only solution available for integrating multiple directory servers. But ever since virtual directories were born, there have been alternatives to meta-directories. So perhaps it's inevitable that the “meta-directory guys” feel threatened by the “virtual directory guys”. After all, we're a competing technology ... but are we really?

Several years ago, Gerry Gebel from the Burton group authored an excellent article on virtual directories, introducing the technology and giving an overview of the companies that were in the field. Since we were one of the pioneers of virtual directory technology, I've had the honor to brief him on our product. He was so kind as to send me the report after it was published, and ever since the Burton Group has been updating the report regularly. What I found very important to note was that Gerry didn't think meta-directories were dead and announce “long live virtual directories”. Instead, he saw the technologies as complimentary.

Gerry was completely right back then, but nowadays meta-directories are just about dead anyway. Let me explain why ... meta-directories use a synchronization approach. They work by propagating changes from multiple places into one place, and then optionally pushing those changes out again to other sources. So it's all about synchronization. Virtual directories, on the other hand work, by pulling data “on the fly” and transposing it “on the fly”.

Virtual directory technology has been around for about five years, and innovative companies like Vodafone and Boeing that saw the light right away were among the earliest adopters. Virtual directory may not be fully mainstream today, but it's a well respected technology, and its advantages and disadvantages relative to the good old (but slightly rusty) meta-directory approach are now well known. So why are meta-directories just about dead? It's because virtual directories have moved on. Nowadays, virtual directory servers such as our Virtual Directory Server include the functionality for synchronization as well, so that users can do the same tasks with a virtual directory that previously only meta-directories could do.

It's all about having the right tools for the right job. Virtualization is an exciting technology that promises very easy integration without the “yet another”  factor (having to create “yet another directory” to copy into). Virtual directories are non-intrusive and can typically be deployed in a fraction of the time that it takes to deploy a meta-directory. Synchronization, on the other hand, is a tool that has advantages in the few cases where virtualization is lacking - such as when data really does need to be copied, or if a data source cannot be relied upon to be permanently available.

So, as virtual directories such as Symlabs Virtual Directory Server take on more and more synchronization features, I can't think of a reason why anyone would want a pure meta-directory any more. Except for those very smart guys who grew up with meta-directory technology, but unfortunately think of virtualization being a "threat" to their good old technology. Move on guys! The future lies with virtual directories, or rather virtual meta-directories - engines that handle both virtualization and synchronization to the benefit of companies and their integrators that deploy them.