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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How Much Flash Do I Need? Part 1

By Jim Sedgwick

Flash, Flash, Flash. It seems that every storage manager has a new favorite question to ask about Flash storage. Do we need to move to Flash? How much of our workload can we move to Flash? Can we afford to move to Flash? Can we afford NOT to move to Flash?

Whether or not Flash is going to magically solve all our problems (it’s not), it’s here to stay. We know Flash has super-fast response times as well as other benefits, but for a little while yet, it’s still going to end up costing you more money. If you subscribe to the notion that it’s good to make sure you only purchase as much Flash as your unique workload needs, read on.

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How’s Your Flash Doing?

By Joe Hyde

Assessing Flash Effectiveness

How’s your Flash doing? Admittedly, this is a bit of a loaded question. It could come from your boss, a colleague or someone trying to sell you the next storage widget. Since most customers are letting the vendors’ proprietary storage management algorithms optimize their enterprise storage automatically you may not have had the time or tools to quantify how your Flash is performing.

The Back-end Activity

First, let’s use the percentage of back-end activity to Flash as the metric to answer this question. Digging a little deeper we can look at back-end response times for Flash and spinning disks (let’s call these HDD for Hard Disk Drives). I’ll also look at the amount of sequential activity over the day to help explain the back-end behavior.

Below is 5 weekdays worth of data from an IBM DS8870 installed at a Fortune 500 company. Although it’s possible to place data statically on Flash storage in the IBM DS8870, in this case, IBM’s Easy Tier is used for the automatic placement of data across Flash and HDD storage tiers. Let’s refer to this scheme generically as auto-tiering. For this IBM DS8870, Flash capacity was roughly 10% of the total storage capacity. Continue reading

Flash Performance in High-End Storage


By Dr. Cor Meenderinck

This is a summary of the white paper with the same title which was the Winner of 2016 CMG imPACt conference Best Paper Award. It is a great example of the research that we do that leads to the expert knowledge we embed in our products.

Flash based storage is revolutionizing the storage world. Flash drives can sustain a very large number of operations and are extremely fast. It is for those reasons that manufacturers eagerly embraced this technology to be included in high-end storage systems. As the price per gigabyte of flash storage is rapidly decreasing, experts predict that flash will soon be the dominant medium in high-end storage.

But how well are they really performing inside your high-end storage systems? Do the actual performance metrics when deployed within a storage array live up to the advertised Flash latencies of around 0.1 milliseconds? Continue reading