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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Noisy Neighbors: Finding Root Cause of Performance Issues in IBM SVC Environments

By Jim SedgwickNoisy Neighbors

At some point or another, we have probably all experienced noisy neighbors, either at home, at work, or at school. There are just some people who don’t seem to understand the negative effect their loudness has on everyone around them.

Our storage environments also have these “noisy neighbors” whose presence or actions disrupt the performance of the rest of the storage environment. In this case, we’re going to take a look at an SVC all flash storage pool called EP-FLASH_3. Just a few bad LUNs have a profound effect on the I/O experience of the entire IBM Spectrum Virtualize (SVC) environment.

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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

5 Reasons Why All-Flash Arrays Won’t Magically Solve All Your Problems

Brett

By Brett Allison

 
IntelliMagic Flash Storage
In the last few years, flash storage has turned from very expensive into quite affordable. Vendors that sell all-flash arrays advertise the extremely low latencies, and those are indeed truly impressive. So it may feel like all-flash systems will solve all your performance issues. But reality is that even with game-changing technological advances like flash, the complexity of the entire infrastructure makes sure that there are still plenty of problems to run into. Continue reading