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June 10, 2014


Vaughn Stewart

Simply a fantastic post - well said Chuck


Paul Carpentier

Sorry, Chuck, with all due respect, but software-defined means exactly what the word says. Standard, virgin, nameless, undefined hardware stem cells that find their eventual groove by means of the genetic material - the software - expressing its functionality. The reason why users are so enthusiastic is because it promises to finally bring back the generic simplicity that got lost in the Stovepipe Era. The proposed use of legacy storage arrays and other pointless complications are simply antithetical to that value proposition and will ruin rather than rescue the desired quantum improvements in TCO.

Chuck Hollis

Hi Paul -- good to hear from you again.

We both know that storage arrays are an extremely popular form-factor these days, accounting for the vast majority of storage spend. Any definition that categorically excludes them on simplistic philosophical terms is naive and impractical.

Digging deeper, almost all arrays use commodity hardware these days, and are differentiated by their software stacks "expressing functionality" as you put it. So, on the face of it, you're discriminating against one class of storage stack vs. another.

Although in a world where the same storage stack is available either (a) packaged with hardware, or (b) running nicely in a virtual machine, it's not clear to me what your argument would look like.

As an example, if someone decides to offer your Caringo storage software pre-packaged with hardware and supported as a unit, does that make your product "bad"?

-- Chuck

Suresh Jasrasaria

Chuck - Great post and lots to think about.

IMO - in addition to being dynamic, one of the key characteristics of software defined storage is when do you bind the application policies to the underlying storage - when the application starts or every time the application processes a data set? For example, when MS Exchange Email starts and all storage that belongs to MS Exchange has the same policy bound to it, or policy binding on the underlying storage happens when MS Exchange processes CEO email vs. a spam email? This leads to the question is the policy related to the application or is it related to the application data? Also, about the definition of dynamic - it means different policy can be assigned to the same storage over time, right? For example - CEO's email from 7 years ago may not have the same policy as his/her email 7 hours ago?

Some things to think about as we create the software defined storage infrastructure.

Chuck Hollis

You bring up a good question.

In my book, the application is responsible for knowing what it wants, in this case Exchange. If Exchange is smart enough to request differentiated storage classes (e.g. one for current email, one for spam, one for retention, etc.) the infrastructure should fulfill those requests. More sophisticated enterprise apps usually have multiple storage spaces, and make decisions about what goes where.

I've had lengthy experiences with the other approach, which is for IT administrators to attempt to impose "application knowledge" externally. It's messy, messy stuff.

The comments to this entry are closed.

Chuck Hollis

  • Chuck Hollis
    SVP, Oracle Converged Infrastructure Systems

    Chuck now works for Oracle, and is now deeply embroiled in IT infrastructure.

    Previously, he was with VMware for 2 years, and EMC for 18 years before that, most of them great.

    He enjoys speaking to customer and industry audiences about a variety of technology topics, and -- of course -- enjoys blogging.

    Chuck lives in Vero Beach, FL with his wife and four dogs when he's not traveling. In his spare time, Chuck is working on his second career as an aging rock musician.

    Warning: do not ever buy him a drink when there is a piano nearby.

    Note: these are my personal views, and aren't reviewed or approved by my employer.
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