[Beowulf] Re: Third-party drives not permitted on new Dell servers?

David Mathog mathog at caltech.edu
Tue Feb 16 08:49:07 PST 2010

Joe Landman <landman at scalableinformatics.com> wrote

> So along comes a drive manufacturer, with some nice looking specs on 2TB 
> (and some 1.5 and 1 TB) drives.  They look great on paper.  We get them 
> into our labs, and play with them, and they seem to run really well. 
> Occasional hiccup on building RAIDs, but you get that in large batches 
> of drives.
> So now they are out in the field for months, under various loads.  Some 
> in our DeltaV's, some in our JackRabbits.  The units in the DeltaV's 
> seem to have a ridiculously high failure rate.  This is not something we 
> see in the lab.  Even with constant stress, horrific sustained workloads 
> ... they don't fail in ou testing.  But get these same drives out into 
> the users hands ... and whammo.
> Slightly different drives in our JackRabbit units, with a variety of 
> RAID controllers.  Same types of issues.  Timeouts, RAID fall outs, etc.
> This is not something we see in the lab in our testing.  We try 
> emulating their environments, and we can't generate the failures.
> Worse, we get the drives back after exchanging them at our cost with new 
> replacements, only to find out, upon running diagnostics, that the 
> drives haven't failed according to the test tool.  This failing drive 
> vendor refuses to acknowledge firmware bugs, effectively refuses to 
> release patches/fixes.

While there is no doubting that these drives didn't work reliably in
your arrays, that doesn't necessarily mean they were "defective".  Just
playing devil's advocate here, but it could be the array controller is
using some feature where there is a bit of wiggle room in the standard,
so that both the disk and the controller are "conforming", but they
still won't work together reliably.  In a situation like that I would
expect the vendor to disclose the issue, so it would be clear why the
disks had to come from A and not B.  As long as the vendor explained the
problem clearly most customers would be fine buying the preferred disks.

It's when the vendor says "you have to use OUR disks" and doesn't tell
you why, and when, as far as you can tell, these are the same devices
that you could buy directly from the manufacturer without the 5X markup,
that things smell bad.


David Mathog
mathog at caltech.edu
Manager, Sequence Analysis Facility, Biology Division, Caltech

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