[Beowulf] what defines "enterprise class" hard drives?
landman at scalableinformatics.com
Thu Aug 5 16:39:17 PDT 2010
On 08/05/2010 05:47 PM, Rahul Nabar wrote:
> I wanted to buy some 1 Terabyte SATA drives for our storage array and
> wanted to stay away from the cheap desktop stuff. But each
> manufacturer has some "enterprise class drives". But is there
> something specific to look for? Most of those seem to have a MTBF of
> around 1.2 million hours and a URE of about 1 in 10^15. The S.M.A.R.T.
> abilities seem fairly standard. Is there a list somewhere of well
> tested drives? Or any recommendations?
Understand that these designations have more to do with product feature
set groupings (marketing groupings) than anything else. The feature set
variations are mostly in the firmware for large groups of product
offerings (lowers BOM costs by using the same physical hardware on all
A "desktop" drive will work much harder to recover an error than an
"enterprise" drive. The former is assumed not to be in a RAID so that
it has to handle errors itself, and the latter is assumed to pass errors
up to a RAID controller.
The head settling logic (not head hardware) may be different, as
"desktop" drives, again, assumed not to be in RAIDs, shouldn't have to
worry about all the vibration maxima at 120Hz, 166.7Hz, and 250Hz (for
7200, 10k and 15k RPM drives), or their beat frequencies and octaves.
"Enterprise" drives have to worry about insufficient vibration damping,
so the firmware pack could have a different head settling/seeking code
"Desktop" drives are assumed to not be spinning 24x7, and have some
interesting power down capabilities, which are anathema to many RAID
controllers (and MD RAID for that matter).
Can you use "desktop" drives in your RAIDs? In some cases, yes. Just
be careful with this.
This said, I'd strongly recommend extended testing. As we have
discovered during some of our testing in this area, some "desktop" (and
in this vendors case, their "enterprise") drives take ... er ...
liberties with the specs, and can, and do wreak havoc on RAIDs (which is
in part why we no longer ship this particular vendor's drives).
Joseph Landman, Ph.D
Founder and CEO
Scalable Informatics, Inc.
email: landman at scalableinformatics.com
web : http://scalableinformatics.com
phone: +1 734 786 8423 x121
fax : +1 866 888 3112
cell : +1 734 612 4615
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