Western Digital Corp's HGST unit has brought out 4 and 6TB nearline platter-reduced disk drives with an 8TB drive on the way.
The Ultrastar 7K6 has four platters, and 4TB and 6TB capacity points. The previous 7K600 had 2, 4, and 6TB capacities with five platters needed for 6TB. By increasing the platter capacity to 1.5TB, HGST has been able to get rid of a platter and read/write head, saving cost and power.
The 7K6 is said to be 12 per cent faster than the 600, although it spins at the same speed, 7,200rpm, and has the same 6Gbit/s SATA or 12Gbit/s SAS interfaces. The buffer size has doubled to 256MB.
It is designed for 24x7 operation, has a 2 million-hour mean time before failure rating and a five-year limited warranty.
Interestingly, HGST introduced its first helium-filled drive, the Ultrastar He6, in November 2013, and that needed seven platters for its 6TB capacity, with 875GB per platter. Traditional air-filled drives are cheaper to manufacture than helium-filled drives, and four-platter drives are simpler to build and operate than seven-platter ones.
So it has, in a way, resurrected the 6TB air-filled drive, sending the helium drives up the capacity scale as it were.
Why? WDC says these drives are for corporate data centres having data set sizes smaller than those found in hyperscale environments. They can use these 4 and 6TB drives for Big Data applications such as analytics and distributed file systems. Also, it says, many traditional data centre systems still rely on moderate capacity points for RAID-based block-and-file systems.
Brendan Collins, Western Digital's marketing VP for the Devices Business Unit, said: "Today, mid-range applications are preparing to move from 1TB and 2TB configurations to higher capacities."
And here WD is with these new cost-effective spinners "allowing OEMs to offer data centres a solution to keep Big Data on-premises, rather than transition entirely to the cloud".
Presumably the marketeers have done their research and when WD says the sweet spot capacities for these applications are 4TB, 6TB and 8TB, it is the case.
WD will introduce a 7K8 air-filled drive with 8TB capacity later this quarter. It will have five platters, meaning 1.6TB/platter – virtually double that of the 7K600.