Helium Hard Drive – Differences from conventional HDDs

Helium Filled Hard Drives…. Will They Take Off ?

(see, the jokes have started already and the article hasn’t even begun yet!)

The announcement late last year that the HGST (Hitachi Global Storage Technologies) division of Western Digital were planning to launch a range of helium filled 3.5” hard drives aimed at the high level server and data centre market, may have taken some by surprise but HGST themselves say that these have been under development for some time. So why is good old fashioned air no longer good enough to spin platters around in? HGST have outlined the benefits thus:

Turbulence – Spinning current disk platters at speed results in air turbulence which induces wobble in the platters and makes it difficult for the read/write heads to accurately follow the data tracks. Helium only has around 15% of the density of air, this significantly reduces this turbulence allowing the data tracks to be closer together and thus increasing areal density or the amount of data per square inch of platter surface.

Drag – The use of helium reduces the ‘drag’ or internal friction experienced by the drive motors which correspondingly use almost 25% less energy to achieve rotation which also reduces the operating temperature of the drives by up to 5 degrees.

More Platters – The 2 factors outlined above are expected to together allow the use of thinner lighter platters and allow them to be closer together such that the maximum number of platters could rise from 5 to 7 within the same size chassis whilst the overall weight might reduce by nearly 30%. These 3 gains put together could see overall drive capacities increased by around 40%.

Less Space – With the same sized disks having significantly higher capacities, the physical size of data centre servers could reduce for the same capacity or allow greater capacity for the same size.

Hermetically Sealed – In order to keep the helium from escaping the new drives will need to be hermetically sealed to an even greater degree than conventional drives already are. This should reduce even further the possibility of moisture or particulate contamination occurring and allow helium filled drives to operate in more extreme environmental conditions.

This all sounds highly promising but what are the associated challenges and why has Seagate’s Senior Manager of Corporate Communications expressed doubts as to the viability of helium drives?

The Challenges…

Keeping The Helium In – Helium is the Steve McQueen of elements, it is very, very, good at escaping. The aerospace industry actually use this property to test for microscopic leaks in systems by filling them with the gas and ‘sniffing’ for any that escapes. All this adds up to a headache when trying to seal a drive sufficiently to keep the slippery helium in for the life of the drive.

Pressure Relief – A conventional hard drive is already fairly well sealed to prevent the ingress of contaminants, and because of this arrangements have to be made to relieve any changes in air pressure or else the drive is liable to explode or implode if it is transported on an aircraft for example. This is conventionally achieved using a vent hole covered in a membrane that allows the passage of air molecules but not larger particles. This would be like an open door to helium molecules so how pressure relief will be addressed when using helium or whether this is unnecessary are points to ponder.
Helium Supplies – Helium is a finite resource, global production fell sharply last year whilst demand is increasing, especially in China and India. This is likely to add up to prices rising as quickly as a weather balloon. Could this also serve to make helium a regrettable choice of filling for hard drives.

Data Recovery – Though data centres and the other types of users that helium drives are targeted at generally safeguard their data to a high degree by the use of RAID’s and other redundancy features, nothing is perfect. There will always come the time when Data Recovery Specialists are called upon to try and recover that crucial set of data from a drive that has failed. Such failures commonly require replacement of the internal parts, read/write heads for example and this has to be carried out in a cleanroom or other such facility to prevent the delicate internals being contaminated with disastrous consequences. If these Data Recovery heroes now also have to try and work in an atmosphere of pure helium the consequences are likely to involve more problems than just some squeaky voices!

All in all, though helium would seem to offer benefits to a market seemingly desperate for ever more capacity, speed, efficiency etc. it is to be hoped that the manufacturers have both considered such factors and found long term satisfactory answers to the challenges they face.