[zfs-discuss] Are HGST (Hitachi) Ultrastar and Deskstar the exact same drive?

[Uncle Stoatwarbler]

On 01/12/14 23:11, Joe Goldthwaite wrote:
> I'll do that once I get them hooked up and I'll let you know.
> 
> On Mon, Dec 1, 2014 at 4:07 PM, Durval Menezes <durval.menezes at gmail.com
> <mailto:durval.menezes at gmail.com>> wrote:
> 
>     Hello Joe,
> 
>     I would be surprised if there aren't any firmware differences
>     between the two. If you can, please post the output of "smartctl -a"
>     for each drive.

The "not visible" changes I can think of are likely to be:

1: Better bearings (supported on both ends)

2: Beefier positioning coils (or higher allowed seeking currents. Either
way translates into higher power consumption) to give greater vibration
tolerance.

3: Greater CRC checking

When you look at enterprise vs domestic drive specs the two things that
usually stick out like a sore thumb are that the enterprise units
usually suck a _lot_ more juice and the silent error rate is usually 1-2
orders of magnitude better (1 in 10E15-16 instead of 10E14)

This must be a common question, as Hitachi have a document on the
differences:

http://www.hgst.com/tech/techlib.nsf/techdocs/77F8DE9679CE7E3C8625765C005CC589/$file/Compare_UltrastarDeskstar_TB_final.pdf

It's pretty much as I summarised - plus the ultrastars tend to have more
cache.

looking elsewhere for power usage. it's the difference between 8 and 12
W. Some of that will be the factors above, the other thing not mentioned
is that the Ultrastars are likely to have a more powerful CPU on them to
handle heavier crc loads.



> 
>     Cheers,
>     -- 
>        Durval.
> 
>     On Dec 1, 2014 8:19 PM, "John Drescher" <drescherjm at gmail.com
>     <mailto:drescherjm at gmail.com>> wrote:
> 
>         > I had ordered the cheaper Deskstar drives for my old ZFS
>         array. I ordered
>         > three replacement drives last week and they came in today. I
>         noticed that
>         > one of them was actually an Ultrastar drive.
>         >
>         > I have both drives side by side and they look *exactly* the
>         same.  Every
>         > specification is identical except for the warranty.  The
>         Ultrastar has 5
>         > years compared to 3 years for the Deskstar.
>         >
>         > Is this just a marketing gimmick? Do they come of the same
>         manufacturing
>         > line and HGST just charges more for the extra warranty?
>         >
>         > I'm just curious if anyone has any inside information on
>         this.  In the
>         > future when they die, I'll probably take them both apart to
>         see if I can see
>         > any differences in the internals.
> 
>         Enterprise drives are supposed to have better components and undergo
>         more rigorous testing.
> 
>         John
> 
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