Cisco Blogs

On Graphs and Plugging Devices In

Enjoying being back in the office after a few days of travel and lots of wonderful customer visits at CiscoLive (ne Networkers) the other week. A special thanks to everyone who did the Video Blogging with us, some of those were pure comedic genius, others quite insightful. But on to today’s point or thought du jour….Power draw is not an absolute. Devices will vary in the amount of power it takes throughout the course of time in which workload is processed, sometimes a switch is forwarding packets, sometimes not, sometimes it needs buffers, sometimes not, some traffic takes more lookups than other traffic, and so on so forth. i.e. power draw is variable based on the type of workload being done.If we can take this as a given that would help me a bit here. I would like to offer up ‘nominal use case’ test results for most/many of our products showing how much power they draw. Right now we have moved forward and provide an accurately measured number based on the data center devices being resident in a controlled temperature facility operating somewhere int he 20-25C range. This is available on our Data Center Assurance Program tool today. In the future though I see this less as an absolute, and courtesy of a good discussion with Paul Marcoux I see it as more or a graph with multiple slopes represented.We need to show power draw under different load factors, in different thermal conditions, with different features turned on or off, and in the end still provide a nominal use case number for planning purposes to get us started with proper planning information.This begs the question though- why did one of our competitors recently shout from the rooftops while wrapping themselves in a green flag and decrying the ‘Cisco Energy Tax’ and talk about how much more efficient their infrastructure is… …when the test had the switches unplugged, no traffic going them, and no real-world features in use? I think I may have to offer an answer, spicy/snarky as it may be: Because for this competitor in particular the nominal use case is that their infrastructure remains unplugged, with no traffic going through it, with no real world features turned on? I am not sure the industry will ever, or could ever, resolve to a one-size fits all test scenario. What we can do is test as accurately as possible, inform openly about what our products can and cannot do and how efficiently then can do this function, and continue to innovate in ways that will ultimately reduce the power draw required to process workload, store the results of it, and communicate to other servers, storage, apps, and end users. dgP.S. the ultimate problem though, and challenge, is that which scenario below is best?1) Business Problem A uses Application X. It runs on 100 Quad-Core servers at 85% efficiency via a superior interconnect that enables built-in clustering and automated load balancing. It has a distributed clustered storage file system with 65% storage utilization efficiency. 2) Same Business Problem A using Application Y. It runs on 10 Dual-Core Servers at 15% efficiency on a standard Ethernet network. It uses a central SAN (eitehr FCoE, iSCSI, or FC to avoid argument) and the storage utilization is also at 65% efficiency.By some measures Scenario 1 is most effective. By other measures Scenario 2 is. The challenge to those that intend to standardize power draw measurements is to ensure that your test methodology picks the right one.

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