Pure’s unique Evergreen ™ Storage model sounds great in theory, and for many who are new to Pure, it even sounds too good to be true. So let’s take a look at how it works in practice using a real-life generational upgrade at ExponentHR as an example.

ExponentHR is a leading HRMS (Human Resources Managment System) SaaS provider that streamlines payroll, benefits, employee self-management, and other HR type services. It’s no surprise their end-user experience is a key differentiator for their business – their services need to be up and running at full performance 24×7. ExponentHR had been running our FlashArray 400 series in production for a couple years and were excited to make the move to our next generation FlashArray//m. Thanks to the Pure EvergreenStorage model, they upgraded software, controllers, and expanded their capacity all online, non-disruptively without any performance impact.

Incredibly, they performed this generational upgrade simply and easily
in a few hours on a Monday afternoon, in other words in full production.

“Nobody had a clue that we just did a major storage upgrade.”
– Chris Gurley, Senior Network Engineer, ExponentHR

It was like no other upgrade they had experienced before – read on for the details!

Evergreen Storage As Experienced by SaaS Leader ExponentHR

Let’s take a look at their actual upgrade, step by step. You can also check out the video.

The Pure Storage FlashArray 400 series arrays have two physically separate controllers. So, step 1 is to remove the secondary controller. No complicated shutdown or migration procedures – simply unplug it and pull it out.


All Pure Storage FlashArrays reserve an entire controller to support your business so removing the first controller has no impact on performance, let alone availability. Applications keep on humming at full speed. In the space left behind by the first controller we now insert the Pure FlashArray //m chassis, which has two new controllers inside, as well as an Infiniband expansion card to provide temporary connectivity between the old and new controllers.

With the chassis in place it’s time to cable it up. And of course we re-cable the existing expansion shelves so they are connected to the Pure FlashArray//m in addition to the Pure FlashArray 400. In keeping with Pure simplicity, there are only 6 cables required once the upgrade is complete: 2 fiber channel cables for storage IO, 2 Ethernet cables for management, and 2 power cables. Pure storage cables are even designed to only install one way to minimize mis-cabling and ensure a non-disruptive experience.


Once the controllers are cabled up, high-availability (HA) is established between the primary Pure FlashArray //m controller and the remaining original FlashArray 400 series controller, which then fails over non-disruptively. At this point a FlashArray//m controller is serving data and remains in HA with the original 400 series controller.


With the FlashArray//m now serving data, the remaining original 400 series controller is simply unplugged and removed.

Next up, we establish full HA between the two FlashArray//m controllers inside the chassis. With that, the upgrade of controllers and associated software is complete, without any performance or availability impact.


Two key drivers of ExponentHR’s controller upgrade were (a) the need to expand their capacity and (b) increase density to save space. So, the final upgrade step is to add capacity via Flash Modules right into the FlashArray//m chassis, again, completely non-disruptively. So where the FlashArray 400 series kept all capacity in external shelves and required a dedicated 4U for the two controllers, the new FlashArray //m has a chassis design which houses controllers as well as up to 40TB of raw capacity, all in 3U.

Putting the glowing orange Pure bezel on the front of the chassis completes the picture. And that’s it! ExponentHR doubled their capacity and modernized their array without any applications blinking an eye. That is the power of the Evergreen Storage model.

For more details on how customers upgrade non-disruptively from one generation of Pure to another, you can check out this great post.

Evergreen Storage for Everybody

If you are considering a tier 1 disk-based storage purchase, wouldn’t you rather get 100% flash storage instead? And if you are considering an all-flash storage purchase, wouldn’t you rather get significantly more effective capacity from every terabyte of raw flash? If so, then take the Pure Challenge – and meet with us!


Here’s what we expect you will find when you do: First, you can get our all-flash storage for the same price or less than equivalent disk. Second, every terabyte of our raw flash can yield 50% more of the effective usable capacity your applications demand, when compared to other all-flash arrays. Sound incredible? Our industry leading data reduction and unique evergreen business model make it possible. But don’t take our word for it – take the Pure Challenge and find out for yourself. You’ll quickly appreciate why our customers recommend us so strongly that we have become the #1 recommended technology vendor* globally

If you like what you see we’ll even coordinate a buy back of your existing disk array and, where applicable, give you credit to help offset remaining maintenance on that array (applies only to initial purchase). Take the Pure Challenge and experience what it means to say hello to what’s possible – today.

*based on Satmetrix 2015 NetPromoter Score Global B2B Benchmarks

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