back to article Talk about a positive mental pl-attitude: WD Ultrastars shed disks without hit to capacity

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 …

  1. Anonymous Coward
    Anonymous Coward

    They'll still be priced in multiples of 1TB...

    So what difference will it make? i.e. 8TB drive will be approx 4x the price of a 2TB one.

    Seagate / WD seem to be price fixing larger capacity drives. It's about time they were investigated, as said pricing 'virtually' per 1TB, not based on the cost of the actual hardware, to produce such capacities.

    Doesn't help that some of their biggest users are currently Governments/Security Services, so don't expect any investigation anytime soon.

    1. conscience

      Re: They'll still be priced in multiples of 1TB...

      Couldn't agree more RE cartel pricing. This is pointless for HDD customers unless the RRP falls below the current prices. If not, the only news here is WD/HGST's profits will go up.

    2. phuzz Silver badge

      Re: They'll still be priced in multiples of 1TB...

      There's usually, or at least, there used to be, a sweet spot, where the price/GB was best (about three years ago it was 3TB drives).

      I've not looked closely at HDD prices for a while but I'd be surprised if it wasn't the case.

      Actually, I've just had a look and for all three main manufacturers (WD, Seagate, Toshiba), there's a noticeable uptick in price after 4TB:

      eg for WD:

      1TB £41

      2TB £57

      3TB £80

      4TB £90

      6TB £155

      Conclusion, 4TB drives are still the way to go, unless you can find a deal on something larger (also worth checking external drives too, occasionally it's cheaper to buy one and rip it out of it's case).

  2. Mage Silver badge

    6TB in air

    I'd worry too how long Helium STAYS in drive. Air sounds good.

    I wonder what the shelf life of the data is when powered down?

    1. Solviva

      Re: 6TB in air

      You only have to keep everything else out... If the helium tries to escape, it creates a lower pressure within the drive and nothing else can than come back in to normalise the pressure, since the barrier is small enough to let only helium pass. Take the drive to space or put it in a vacuum and you might se issues though!

      1. razorfishsl

        Re: 6TB in air

        Actually no.

        The drives pressures or generate negative pressure depending on the temperature profile and altitude.

        So it will automatically be subject to pressure variations.

        Then there is the issue of what happens during a drive failure. you can bet with a helium drive your chances of recovery are zero, since the air would be to dense to recover the data

  3. Luiz Abdala


    I know, whoever buys these large drives is not after speed, but capacity... but how fast are they?

    I bet somebody is planning to use one of these for backup, or something that requires a bit of speed, somewhere.... Like CCTV storage, or something similar. Whatever, there must be an use case that requires ginormous drives, and some performance combined.

    Not even a brochure mention?

    1. Luiz Abdala

      Re: Speeds?

      [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.]

      Something 12% faster than another thing. And the speed interface means SQUAT to spinning rust drives. Not a single MB/s metric out there.

      Fine, I will look for performance charts of them in Anandtech or something.

      1. Mage Silver badge

        Re: Speeds?

        Higher density per track means higher speed per bit at same RPM. Just as outer edge is "faster" than inner edge (though same RPM).

        The SATA speed is only relevant (maybe) when doing Cache hit RAM I/O.

        Number of tracks has no effect.

        So a 6T drive at same RPM and same number of platters/ tracks as 3T drive could in theoryl be twice as fast at same position on drive. Outer edge maybe about twice speed of inner edge, not sure. It's a very long time since HDD had real fixed physical sectors, where no advantage was taken of higher linear speed as you move head outwards.

        1. really_adf

          Re: Speeds?

          So a 6T drive at same RPM and same number of platters/ tracks as 3T drive could in theoryl be twice as fast at same position on drive.

          Yes but, to a first approximation, the tracks get closer by as much as the bit time gets shorter. End result: sequential transfer rate at a given RPM is roughly proportional to the square root of platter capacity.

          7K600: 6TB / 5 platters = 1.2TB/platter

          7K6: 6TB / 4 platters = 1.5TB/platter

          Predicted improvement:

          (1.5/1.2)^0.5 - 1 = 11.8%

  4. Anonymous IV

    SSD manufacturers' olde saying

    "Plattery will get you nowhere..."

    1. earl grey Silver badge

      Re: SSD manufacturers' olde saying

      I want to know how they get the platypus in there.

  5. Ticowboy

    2 million hour mean time before failure is more than 200 years. If it lasts half that long it will be a good buy.

    1. conscience


      If only!

      I have heard of drives lasting decades when they're never switched off, but more often it's the repeated on/off power cycles that kills them before the MTBF figure.

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