Solid State Disks Fill The I/O Gap

CloudData StorageDatacentreSoftwareStorage

The I/O controller was once a humble device, but it’s the key to creating evolved storage systems that get the best out of solid-state and spinning disk  evolved into a data conditioning platform

The I/O card may seem a lowly part of the server, but Adaptec’s chief executive, Sundi Sundsaresh, reckons it’s a centre where it can innovate – to help companies reduce their expenditure and their carbon footprint.

I/O used to be all about performance, he said to eWEEK Europe on a visit to London, but no longer: “We have shifted our focus to improve utilisation and scalability – focusing on the economics to reduce capital costs and help customers achieve their green objectives.”

“Controllers used to have a few elements, and our differentiation was how well we handled failure modes around RAID, and how well we interoperated with other parts of the ecosystem,” says Sundaresh.

Now, by applying intelligence in the I/O path, he reckons Adaptec’s products gain take a much more influential role, evolving from humble controllers to a “data conditioning platform”, by using the intelligence they garner from looking at I/O patterns.

Any increase in efficiency they can offer will add to the data centre’s bottom line, he explains – since data centres make their money on the difference between the price they can charge for their services and the cost to themselves to deliver them,

There’s a logic to applying I/O intelligence in the card itself, he explains, as it need not affect the operating system or applications on the server. “Companies don’t have time to application or OS level tuning,” he says.”You can get the benefits without making those changes.”

In the company’s latest product, the MaxIQ, announced today, that intelligence is used to cache frequently-used data on a solid state device.

Solid state disks (SSDs) could be the answer to what he calls the “I/O gap”, caused by the fact that, while hard disk prices have tumbled, their performance has not rocketed the way server performance has: “CPU performance has increased 175 times since 196, with multicore, but hard disk performance has only increased 1.3 times.”

While SSDs offer a steep climb in performance, they are still expensive, so Adaptec intends to use its data conditioning role to bring them in as a cache. As well as increasing performance this could also cut power, but allowing the controller to spin down the hard disks more often – a simple move which, it’s been worked out, could save the equivalent of gambia’s entire power usage.


The controller can boost power management, using the I/O data, and intelligently place and route data, he says: “That’s where we start adding value.” In June Adaptec added zero maintenance cache protection, that eliminates the need for batteries on the RAID controller: “That’s really about saving administration costs,” says. “Once a year you have to open the box and replace the battery module. With Flash based cache protection, we’ve
eliminated the need to do that.”

Breaking the trade-off

“A few years ago, we saw the deployment model changing to broad web-based cloud deployments,” he says. “We saw the shift from SCSI to SAS, and from 3G to 6G – and then we saw the change to SSDs.”

SSDs set up a trade-off between the high performance they provided and the high capacity of hard disks. “We saw the opportunity to break that trade-off. We won’t be the only ones, but we are the first.”

In future the trade-off will remain, says Sundaresh, and the performance curves will diverge: “SSDs follow Moore’s Law – but the hard drive has a head start [an unintentional pun].”

While the sweet spot for SSDs is only 32GB, cheap SATA drives have nothing to fear. “There’s a class of drives where it’s all about price per Gig – they’ll hold the bulk of the cold data, so we’ll see hybrid systems for a long time.”

Higher performance hard drives will be first against the wall: “If you’re using a short-stroke SAS drive, chances are you’ll start replacing those with SSDs in the next few years, because the price-performance curves are converging. That’s why all those vendors are scrambling to get into SSDs.”

That’s a bit ironic he says: “Drive manufacturers have used the high-performance sector to develop their technology. What will they do if that goes away?”

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