The Storage Compass

I am sure many people in IT get pissed with IT jargons and terminologies. More so if it is a customer, especially when he or she is not well versed with the fundamental concept behind the technology architecture.

Even after 20 years, with most of it in storage, I have a hard time switching from one vendor’s jargon to another (sometimes). But it has gotten harder for me lately, since I teach ONTAP courses for NetApp, EMC Cloud Infrastructure and doing my work with the ZFS stuff. Soon, I will take on EMC VNX, Information Storage Management (ISM), Big Data courses as well, and I also plan to do some Nexenta training too.

Who would know that an ONTAP NAS volume would be known as file system in EMC VNX for File (aka Celerra), and a data set in ZFS? Or a ONTAP aggregate is almost like a ZFS pool but with some differences or a clone might be called a replica in HDS and so on …

In fact, all the definitions above could be wrong because I am getting confused. 😉 You would be too if you have to switch from one vendor’s jargon to another. And the poor EMC pre-sales who has not been with any other vendor except for EMC all his career would have a hard time rewiring his brain if he had joined another vendor like NetApp.  Or IBM, or Dell, or Oracle or anyone for that matter.  No wonder the customers are pissed. 

Fear not, because there is help.

Remember the days when we first encountered our first networking lesson. What’s the first thing you and I have to memorize (often by heart)? Look the diagram below and tell me what it is:

Yes, it is the famous OSI 7-Layers. There aren’t many commercial implementations of the OSI 7-Layers (except for maybe the X.25 protocol suite) but it did help us understand networking. It helped us understand what are frames, packets, datagrams, etc without the fancy schmancy vendors’ jargons.

Well, guess what? There is one in storage networking as well, and it is called the SNIA Shared Storage Model (SSM). And it is just as important as the OSI 7-Layers, because it helps us understand the storage architecture landscape and how every piece fits together in totality. It is defined in a common vocabulary and industry accepted standard definitions and terminology, minus all the artificiality of the vendors’ jargons. It is THE STANDARD MODEL for storage architectures. The second and the latest version of the SSM looks like this:

By studying the SSM, anyone (I hope), would be able to understand where each component fits, how they communicate and interact with each other, and the relationships and dependencies that are involved.

When layered with applications and the storage networking technologies, one would be able  figure out the SAN and the NAS, differentiate the components and the protocols and understand the pros and cons, AND the whys of disparate storage architectures. Here are 2 examples of a layered view of both SAN and NAS:

In fact, the division and categorization of DAS, NAS and SAN are very well laid out in the SNIA Layered View below:

The SNIA SSM does not leave out Tape technology as well and have included Tape in a variation of the SSM model below:

There is an old, but very practical example of how the SNIA Shared Storage Model is applied in a real life environment. This article was part of the book called “Designing Storage Area Networks: A Practical Reference for Implementing Fibre Channel and IP SANs, 2nd Edition” written by Tom Clark. Sadly Tom Clark passed away on February 13th 2010 and his blog remained as his online memorial space. Tom has been one of the pioneering stalwarts of SNIA.

I had the honour of meeting Tom in the year 2000, at the Quantum Asia Pacific event in Langkawi. I told him how his book (the first edition) gave me the foundation and solid grounding in storage networking. His book helped me passed my SNIA Fibre Channel Professional certification in 2001.

Sentimental feelings … but back to SNIA SSM.

Coupled with the SNIA Dictionary (recently updated in 2012), the SNIA Shared Storage Model is THE COMPASS for everyone involved in storage, information infrastructure and information management, just like the OSI 7-Layers.

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About cfheoh

I am a technology blogger with 30 years of IT experience. I write heavily on technologies related to storage networking and data management because those are my areas of interest and expertise. I introduce technologies with the objectives to get readers to know the facts and use that knowledge to cut through the marketing hypes, FUD (fear, uncertainty and doubt) and other fancy stuff. Only then, there will be progress. I am involved in SNIA (Storage Networking Industry Association) and between 2013-2015, I was SNIA South Asia & SNIA Malaysia non-voting representation to SNIA Technical Council. I currently employed at iXsystems as their General Manager for Asia Pacific Japan.

7 Responses to The Storage Compass

  1. Pingback: The Storage Compass « Storage Gaga

  2. We down here @ Brazil finishing the SNIA Dictionary Portuguese version 2012 , I stakeholding a great efforts thruout last 4 years giving visibility to Brazil market over SNIA e Industry activities. thumbs up to I becoming a Fan of it ! — Valdir Adorni.

    • cfheoh says:

      Thanks Valdir for reading and supporting my blog. I understand that Paul Talbut is helping out with SNIA Brazil.

      I wish you and your team all the best! Keep storage going strong! Yeah!



  3. Dieter Kuefner says:

    I do agree completely to your post. This is really something annoying. As I’m working for an IT Service provider we are using systems from multiple vendors and there are always misunderstandings, irritations and uncertainty in the communication between colleagues and/or vendors. I’ll try to use the terms from the SNIA dictionary since years in my internal documentations or when answering customer RPQ’s.

    • cfheoh says:

      Hi Dieter

      In my experience, I try to learn all sorts of terminologies and jargon, but I clarify with the vendors what they mean. The SNIA SSM is meant as a guideline. Even this week, as I am teaching the SNIA Storage+ class, I try to learn from what each vendor’s definition is. The reason is you can get better acceptance if you learn their “language”, but at the back of my mind, the SSM model will be what I fall back on.

      People will accept things better if things are spoken in something they like to hear. 🙂

      Good luck to you and all the best!


  4. gminks says:

    Great post! I used to develop training for EMC, now I work for Dell. Understanding the basic framework is so important so you have the vocabulary to ask vendors what they really mean when they name things certain ways. I’ve been doing some research for a project and I don’t understand why the startups feel the need to rename everything. But then again I guess no one ever standardized how we call things. Sure makes things hard to explain. 🙂

    • cfheoh says:


      Thanks for reading my blog. I ran through a few rounds of the SNIA Shared Storage Model. It is good to put things into perspective, but in the end, there is a sense of “customer loyalty” from EMC or NetApp or any other storage vendors. It is difficult to change mindsets and SNIA SSM is a good start for people just getting into the storage networking industry.

      All the best to you and thank you


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