How Much Flash Do I Need Part 2: Proving the Configuration

By Jim Sedgwick

Before making a costly Flash purchase, it’s always a good idea to use some science to forecast if the new storage hardware configuration, and especially the costly Flash you purchase, is going to be able to handle your workload. Is your planned purchase performance capacity actually too much, so that you aren’t getting your money’s worth? Or, even worse, is your planned hardware purchase too little?

In Part 1 of this blog, we discovered that our customer just might be planning to purchase more Flash capacity than their unique workload requires. In part 2 we will demonstrate how we were able to use modeling techniques to further understand how the proposed new storage configuration will handle their current workload. We will also project how this workload will affect response times when the workload increases into the future, as workloads tend to do.

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Modeling – Is it for You?


By Lee LaFrese


In social situations, people sometimes bring up what they do for a living. When I say, “I am a Storage Performance consultant,” I usually get blank stares. When I am asked for more details, I usually reply “I do a lot of modeling.” This often elicits snickers which is entirely understandable. Anyone that has met me knows that I don’t have the physique of a model! When I add that it is MATHEMATICAL modeling that I am talking about it usually clears up the confusion. In fact, folks are typically impressed, and I have to convince them that what I do is not rocket science. Of course, a lot of rocket science is not “rocket science” either, if you use the term as a euphemism for something very complex and challenging to understand. In this article, I will try to help you understand how computer system performance modeling is done, specifically for disk storage systems. Hopefully, you will have a better appreciation of performance modeling after reading this and know where it can be used and what its limitations are. Continue reading