Unpacking the data services vs performance metric debate. Why we should stop the IOPS wars and focus on latency.

IOPS is not that important for most data centers today because flash arrays are so much faster than the storage they replace. That’s why the first post was titled IOPS is not the key number.

The point of that post was that in the context of all flash arrays the greater benefit comes from lower latency, not more IOPS. Everyone agrees more IOPS aren’t much use once the needed threshold value is crossed. But lower latency is a lasting benefit.

The second post Data services more important than latency? Not! was more controversial. I was responding to a Twitter thread where an integrator CTO first asserted that customers don’t care about latency (true, but they should) and then questioned the datacenter savings due to flash performance.

My response: where has this guy been for the last 10 years? Hasn’t he noticed what flash has done to the market? Could he not wonder why?

What his tweets underscored is that we as an industry have done a poor job of giving customers the tools to understand latency in data center performance and economics. We clearly don’t understand it well ourselves.

Safety doesn’t sell
Compare this to auto safety. 50 years ago Detroit argued that “safety doesn’t sell” because consumers didn’t care about it. They fought seatbelt laws, eye level brake lights, head restraints, airbags and more because, they said, consumers don’t want to pay for them.

Today, of course, safety does sell. There are easily understood (and sometimes controversial) benchmarks for crash safety that make it easy for concerned consumers to make safety-related choices. Not all do, but clearly safety is a constant in mass-market car ads today, showing how much market sentiment has shifted as consumers understood it meant keeping their children, family and friends safer.

In regards to latency, the storage industry is where Detroit was 50 years ago. People like the CTO, who should know better, don’t.

The VMware lesson
VMware offers a more recent lesson. They offered a simple value proposition: use VMware and get rid of 80% of your servers.

That wasn’t entirely true, but it encapsulated an important point: you can save a lot of money. Oh, and there are some other neat features that come with VMs, like vMotion.

Give people a simple and compelling economic justification and they will change. But it has to be simple and verifiable.

Data services platform?
The rapid rise of the “data services platform” meme is a tribute to EMC’s marketing. Google it and you’ll see that until EMC’s SVP VMAX, Fidelma Russo wrote about it a couple of weeks ago, it wasn’t even a thing. Now we’re debating it.

Likewise, asserting that data services are more important than performance contravenes 30+ years experience with customers. Yes, data services are important – mostly because today’s storage is so failure prone – but give a customer a choice between fast enough and not fast enough with data services and you’ll quickly see their place in the pecking order.

EMC is changing the subject because the VMAX is an overpriced and underperforming dinosaur. Until they get the DSSD array integrated into the VMAX backend, it will remain underperforming.

The StorageMojo take
Is performance – thanks to flash arrays – a solved problem? Those who argue that flash arrays are fast enough for most data centers seem to think so. And they may be correct for a few years.

It’s easy to forget that we’ve had similar leaps in performance before, most notably when RAID arrays entered the scene almost 25 years ago. It took a few years for customers to start demanding more RAID performance.

What happened is what always happens: the rest of the architecture caught up with RAID performance. CPUs and networks got faster; applications more demanding; expectations higher.

Storage is still the long pole in the tent and will remain so for years, if not decades, to come. In the meantime we need to refocus customers from IOPS to latency.

How? A topic for future discussion.

Courteous comments welcome, of course.