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The “Power” of a SAN Switch

I was in a meeting with several individuals from a large enterprise customer in Europe a few days ago and while presenting our strategy and vision for the Data Center, one of the people in the room interrupted me (quite abruptly, I might add) and he said something that could be paraphrased like this:

“œOK, I got all that stuff, but I have to make a decision by next month about upgrading my Storage Area Network and you are not helping me here. I am talking about real stuff, not the marketing fluff you are giving me and Cisco has not yet explained why I should consider your MDS directors vs. just keep going with my old stuff that works just fine, by the way!

I wish I could have recorded the question exactly as he asked it, because that would probably give you a much better idea of how important making a business case for SAN migration was for him. I questioned him a bit more about migration and he explained that his boss (the CIO, who was in the room as well) asked him to look into Cisco to replace the existing environment (obviously the Cisco account team knew how to sell high) but he had not seen any good reasons to change the status quo yet.I took a deep breadth and thought about how to answer that question. As good as it can possibly be, the marketing”story” was not going to make an impact quickly. The other challenge for me was that I could come up with a list of things — having been on the MDS engineering side for quite a while — that I could use to make strong arguments for making the move to Cisco, but I did not have the luxury of time or the audience’s patience to go through all of them in detail. I only had one shot and I needed it to be the best one. With the little time I had, I decided to go for something that is very”trendy” amongst Data Center managers these days:”power efficiency”. In support of the meeting, I had brought a copy of a recent report that has just been published by the Enterprise Strategy Group (ESG) on”Building Power Efficient Solutions With Cisco MDS 9000 Directors.” This report essentially demonstrates (through actual testing) how you can run more energy efficient storage networks if you leverage some unique features of the MDS like Virtual SANs and InterVSAN routing.I handed the ESG report to the guy and there was silence for a few seconds while he went through the document (I could tell he was just looking at the graphs, not reading the content) and I was sipping some much needed water. At the end he broke the silence and said:

“œI am seeing this for the first time right now and of course I would need to read it through, but it is definitely one of the things we have been considering more and more recently. We are so concerned about our power bills that we have almost considered acquiring the energy company. It might be cheaper!”

His joke (was it a joke?) made me feel better since I knew this issue addressed a critical factor for his SAN environment and migration considerations. Though his answer was not a”Yes, I will buy your MDS directors today!” it was still a good answer for me. Amongst all the topics to highlight quickly, I knew that addressing power & cooling demands was one of the best arguments to use. I was not trying to sell him on features and gadgets; I was giving him something that was important to him and would make made him look prepared when he returned to the table to discuss with his CIO.There were several brochures and documents and notes that were left lying in the room at the end of that customer’s visit, but no sign of the ESG report-

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3 Comments.


  1. Dante Malagrino

    I stand corrected by Brian and I apologize for the inaccuracies in the original post. I guess I have known the ESG for so long that I did not notice they had changed the spelling of their name ;-)I also confirm that the ESG did not actually test the configurations, while their report is based on technical review and analysis. The actual testing”” I was referring to has been conducted in our internal labs at Cisco and can be verified by customers during EBC (Executive Briefing Center) visits in San Jose.In the meanwhile, I must say that power and cooling continues to be a top priority for us and for most of the customers I deal with daily.Stay tuned!”

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  2. Brian Garrett, the author of the ESG report mentioned here, with a couple comments:1. ESG stand for Enterprise Strategy Group, not Enterprise Storage Group. We changed the name a couple years ago when we started covering other industries including security. 2. Although ESG is well known and respected for hands-on validation testing, the power and cooling data presented in the report is based on technical review and analysis, not hrough actual testing”” as stated in the blog.”

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  3. Power and cooling really are the major top of mind issues in the data center today. It seems as if the data center operators have an almost illegal-substance like addiction to compute capacity. I think this breeds an interesting problem-The more work we (as an industry) do to improve the power and cooling efficiencies in the data center the more the operators and administrators will take these efficiency gains and use them to improve the compute density in a given environment.As one friend from a large and storied investment bank told me once, at 70% of physical capacity of a data center we are at 100% of power capacity and our local power company cannot give us more””.I was in a roundtable with Andy Karsner, the Assistant Secretary of Energy, several weeks ago and the entire discussion was centered around data center efficiency issues and how the industry could partner with the government to jointly help. Some of the key points raised at this event were:1) A move to a more efficient voltage than 110v. This could yield significant efficiency improvements without requiring new capital expense for the IT assets. (credit here goes to Andy Bechtolsheim from Sun).2) A common set of efficiency guidelines and measurements for power supplies at different load thresholds. (this is primarily a concern for the server vendors since low-cost white box vendors often skimp here and some power supplies have been seen that rate as low as 50-60% efficiency at nominal loads. This would be ‘Energy Star-esque’.3) The ‘field of dreams’ reality that anything we do to improve efficiencies will not result in power reductions but will result in increased capacity.4) One gent commented that we should raise the operating temperatures of silicon chipsets. That by raising the optimal temperatures from 68F to 70F or so would allow them to run the HVAC less. While at a cursory glance this seems to make sense CPUs take more power at higher temperatures to operate and this would not be a win.5) Server ‘sleeping’ and Virtual Machine integration provides some interesting opportunities- could we move virtual machines to a server in the evening and have a ratio of say 50 or 100 Guest OS’s to 1 physical server and then in the morning move the guest OS back to a dedicated server at a 1:1 ratio.This would allow the servers to use IPMI to turn off at night and Wake-on-LAN to come back online in the morning. 6) The last thing that came up that I found very interesting was that when it got over 110 in August in Northern California we were 385 Megawatts from rolling blackouts in Norcal. Doesn’t really click home for me until I remember that we have some customers building 100MWatt data centers now. Thus we were 4 data centers from rolling blackouts in Norcal – and California as a stand-alone is the worlds’s 6th largest economy. Companies are moving facilities (and thus tax base) out of California to the Colombia river valley, to Phoenix, etc because they are not assured of power grid facilities and self-generation is still perceived as too complex/expensive.While we have created in the networking world data-plane virtualization technologies to reduce the overlap in SANs, more efficiently utilize ports, etc we have not started control-plane virtualization yet on our products. I think the move to integrating control plane and data plane virtualization together between networking products and compute and storage devices will provide interesting new opportunities to lower the power and more efficiently use what we have. Although as to whether we take the energy efficiency gains and return them to the bottom line or increase the compute and storage capacity of a fixed facility I think that is a larger societal issue… What would you do?”

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