The Latent Heat of Flash

The market is heating up and things are about to change.

Latent heat of Flash

When budgets are tight the focus often goes onto the price per terabyte and that can mean storage that is just responsive enough to stop the application owners from beating down IT’s door to complain.

Latency is about end-user Productivity

Over the years, application owners have been conditioned to run their apps on unbalanced infrastructures, usually with storage being the slowest part of the system. A 10 millisecond delay per online transaction has been generally considered acceptable for storage, while the app, the CPU, and the RAM all sit and wait. Not only that, but the way we size for transaction loads is often based on knowing the current peak transaction rate and response time and then allowing a percentage for headroom and growth. The sluggish old system is used to define the speed of the new one.

If we instead fully address the slowest link, improving it 10 fold, the apps run much faster, and as someone who often spends time each day waiting for IT systems to respond, I know that faster systems lead to better productivity.

In my last post I looked at the way some systems respond to the SPC-1 benchmark, often hitting 5 milliseconds read latency at less than half their rated IOPS. With the maturation of flash storage, the time is fast looming when 5 to 10 milliseconds will be considered unacceptable for online transaction processing, and sub-millisecond response will be expected for important apps. 

At what point does the cost equation move away from being based on $/tolerable-TB to $/high-productivity-TB for mainstream transactional apps? It’s hard to quantify the productivity gain from a storage system that is 10 times more responsive. Is it worth double the $/TB? 50% more? 33% more?

An easy place to start is with transactional apps that need up to 20 TB of space, because that’s now relatively easy and cost-effective on Flash, but if you’re like Sprint Nextel and you need 150 TB of Flash then IBM can handle that as well using multiple 1u FlashSystem 820s behind SAN Volume Controller. Sprint Nextel are number one for customer service in their market and the purchase was designed to allow call-center operatives to respond rapidly to customer queries. They are visionary enough to see Flash as a competitive business advantage.

In my earlier post on Flash called Feeding The Hogs I focused on the traditional sweet spots for Flash, but what I’m hearing out in the world seems to be slightly different – the idea that every transactional app deserves Flash performance and a dawning realisation that there are real productivity gains to be had.

For more information on the IBM FlashSystem 820 check out IBM’s Flash product page.

Waiting for the computer


2 Responses

  1. […] the small V3700 with Easy Tier Flash right through to high-end SVC Flash Solutions like the one implemented by Sprint in […]


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