[zfs-discuss] zfs-discuss Digest, Vol 43, Issue 3

Gordan Bobic gordan.bobic at gmail.com
Wed Nov 7 18:03:17 EST 2018


Oh, and I don't thing vacuum filed drives would work with current
technology. Heads are specifically designed to float on a cushion of gas
like the wing of a plane. Without that fraction of a mm of gas keeping the
head afloat, it would cause a "head crash" - where heads scrape onto the
disc and score it, permanently destroying the tracks (and not just the
data), and probably the head itself in the process.


On Wed, 7 Nov 2018, 22:56 Gordan Bobic <gordan.bobic at gmail.com wrote:

> For obvious reasons it is not possible for any current model to have ever
> had millions of hours of testing per drive. :-)
>
> Backblaze are publishing their stats specifically because they are too
> small to buy direct from the manufacturer (10,000 drives at a time). Bigger
> players like Google have to anonymize their findings by makes/models
> specifically because they would lose their discounts. It is most fortunate
> for all of us that Backblaze are publishing their reliability stats.
>
> On Wed, 7 Nov 2018, 21:55 Bzzzz via zfs-discuss <
> zfs-discuss at list.zfsonlinux.org wrote:
>
>> On Wed, 07 Nov 2018 22:03:49 +0100
>> Gionatan Danti <g.danti at assyoma.it> wrote:
>>
>> > Interesting... and condivisible. [my italian is as rusty as my german]
>>
>> > Surely if the manufacturers lie (and
>> > often they do!) we have a problem.
>> > Anyway, give a look here:
>> > https://www.backblaze.com/blog/smart-22-is-a-gas-gas-gas/
>>
>> Hum, one part of the 2nd sentence is pulling attention:
>> "allows the drives to run cooler and quieter"
>> cooler, yes, as He has a very low resistance to temperature,
>> but quieter, I doubt (which pose a question: what is the real
>> relationship between backblaze and WD ? Well, to be more precise,
>> another one too: do you really think such a big customer couldn't
>> get an extra few percent off praising he's supplier's product ?)
>>
>> My contention is to wait a bit more until He HDz other large consumers
>> check or not what backblaze says.
>>
>> Something makes me uncomfortable in the commercial brochure, though:
>>
>> https://www.hgst.com/sites/default/files/resources/HGST-Helium-Technology-BR03.pdf
>> P.3, §2: "Prior to shipping helium-filled drives, we performed long-
>> term reliability testing, with 5,000 drives each running more than 1,000
>> hours (over 5 million combined hours), showing no seal degradation on
>> any of the drives."
>>
>> It is not said, but suggested, in the right line of neuro-science
>> studies (mostly paid by the marketing industry to try to learn how to
>> fool people an easier way) - the incriminated part is the one about
>> the "5M combined hours".
>>
>> Just as if I told you to buy my new car because I made tests using
>> 20,000 of them, making 1000 km each…
>> (20,000,000 combined kilometers ;-p)
>>
>> What is also concerning is the SMART indicator set into the pre-fail
>> type, meaning when your He HD rings the bell, you're doomed because the
>> drive aerodynamics was calculated for Helium fluid, not air.
>>
>> May be vacuum instead of Helium would have been a better idea
>> (disclaimer: I'm not a fluids mechanic specialist.)
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