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Re: Problem with eSATA Port Multiplier

Ron Johnson put forth on 10/2/2010 5:36 AM:
> On 10/02/2010 02:08 AM, Stan Hoeppner wrote:
>> Ron Johnson put forth on 10/1/2010 5:28 PM:

>>> http://members.cox.net/ron.l.johnson/PMP_innards.jpg
>>> http://members.cox.net/ron.l.johnson/PMP_front.jpg
>>> http://members.cox.net/ron.l.johnson/PMP_rear.jpg
>> Ok, so the 4 drive SATA JBOD box has a small cheap hotswap backplane
>> containing the port multiplier chip.  If the problem isn't the cable,
>> it's likely the backplane itself.  I've read many horror stories on the
>> Linux-RAID and XFS lists about cheap backplanes.  Direct connecting the
>> drives to the controller fixes the problem in over 90% of the cases I've
>> seen.
> But how would I do that?

In you case you'd have to test each drive individually, as you
apparently don't have 4 free SATA ports inside your host machine.  Given
the errors you receive, the drives aren't the problem.  It's the cable
or the backplane.

>>        And it's not just "cheap" backplanes that suffer these problems.
>>   I've read cases of reputable whitebox backplanes (SuperMicro for
>> example) having problems.  And it's almost always "active" backplanes
>> that fail--those with with a PMP or I2C chip, or both.  Passive
>> backplanes rarely causes problems, and if they do, they're defective out
>> of the box.  Active backplanes can die over time.  Cross your fingers
>> and hope it's the cable.
>> I forgot to ask earlier:  is this JBOD enclosure a recent addition, or
>> was it working fine for eons and all of a sudden crapped out?
> It never "worked".  I'm only now stimulated to try and fix it.

If the cable doesn't fix it, the way to do so is to order a replacement
backplane from the manufacturer.  I'm assuming the unit you have it out
of warranty.  If not sent it back for repair.

They will probably quote you a price on a replacement backplane so high
that it would be better to buy another complete unit, which is exactly
why they'll shoot you an unrealistically high price.  Then again, they
may simply say they don't sell replacement backplanes/parts of any kind.

If the cable isn't the problem but the backplane is, and if for any
reason you don't want to attempt replacing the backplane, I'd recommend
swapping the drives into a similar product:


I've never used this device, but it's the least expensive eSATA box
Newegg carries.  It's big brother (more expensive) doesn't look any more
capable, although swapping a drive is easier with the more expensive unit.


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