Introducing Target Driven Zoning (TDZ)

Post by Erik Smith (thank you) on Target Driven Zoning

At 9:28 on Tuesday 12/6/2011, the T11 FC-GS-7 working group approved a motion to incorporate the text for “Peer Zoning” that was prepared by Claudio DeSanti (Cisco).  The actual text can be found in the T11 document 11-411v2.  To me this moment marked the culmination of a four year journey to take a concept, get it through a standards body and into a standards document.

Target Driven Zoning (TDZ) is a proposed application that utilizes Peer Zoningto reduce the number of steps required to provision new storage by 50%.  Since many customers have been complaining about the task of zoning for years, I’m proposing to achieve this reduction by eliminating the manual task of FC zoning. 

Just to be clear, while I view introduction of the Peer Zoning functionality as a game changer for FC, I don’t view the completion of this effort as some kind of extraordinary accomplishment, actually there’s nothing extraordinary about it.  These sorts of efforts are started all the time in standards bodies.  Sometimes they result in useful protocols that are implemented by many (e.g., FCoE and FIP).  Other results are implemented by few but they provide a critical requirement for the industry (e.g., FC-SP) and yet others turn out to be interesting academic exercises but are never implemented by anyone (e.g., FC-SCM).  I have hopes that Peer Zoning will fall into the category of “useful technology that is implemented (and deployed) by many” but it’s too early to tell as this point. 

This post is intended to give you an overview of the technology and give you enough information to decide if TDZ is something that you’d like to use in your environment.  I also feel it’s important to give credit where it’s due and with that in mind without the help of Mark Lippitt, David Black, Claudio DeSanti, Bob Nixon and Ralph Weber; this entire effort would still be hopelessly stalled.      

Background

The story starts back in mid-2007.  I was on a conference call with David Black and Mark Lippitt (both with EMC) discussing what would happen if zoning wasn’t used in an FC SAN (as was being proposed in the T11 FC-SCM working group).  In case you don’t know, EMC has a fairly strict best practice called “Single Initiator Zoning” that was created based on lab testing results.  As the name suggests, the best practice states “zones should only contain a single initiator as well as the storage targets it needs to access.”  Because of the work that I had done with fabric scalability, I was pulled into the meeting (somewhat last minute if memory serves) and asked to provide my opinion on what was being proposed.  Now, as most people who work with me will tell you, I typically call things as I see them and the intensity of my voice will vary with the level of conviction that I feel about a given topic.  As a result, my reaction to eliminating zoning was something along the lines of “ARE YOU <bleep> KIDDING ME?” and I proceeded to provide specific reasons why I thought that this was the *SILLIEST* idea I had ever heard of.  Perhaps it was the intensity of my reaction (or the simple fact that David simply didn’t have sufficient bandwidth to create a presentation that contained all of my points), in either case, he eventually asked me to present my list of concerns to the T11 FC-SCM working group at the August 2007 meeting in Seattle.

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