Returning to the title of this thread: 'WD EARS - Is pre-clearing necessary?'

 

The answer is 'no', but this thread provides good evidence why it is a good idea!  It is rare to receive two defective drives at the same time, but it can happen.  I hope your replacement drives are healthy.

 

I've had back to back bad Hitachi drives too.  the 2nd was the replacement for the first.  3rd worked fine.  Rare and a pain ... but it does happen.

OK, both drives failed the writing of zeros test...... and now both drives are going to be on their way back to newegg.

 

Thanks for the tips VCA, when I get the replacements I will take those exact steps. You made it sound like you have a few of these drives.... of the ones that did not fail initially, have they been reliable, or is it still hit or miss if they will flake out?

 

None of my WD drives that have passed a two-pass preclear have developed any problems, so I still think they are reasonable drives to use with unRAID (especially if you run regular parity checks).  These days I keep a spare 2TB drive in my array that has already been precleared, so if a problem develops I can swap it in and rebuild quickly.

 

I did have a strange issue with one of my 1.5TB WD drives which is documented here:

 

http://lime-technology.com/forum/index.php?topic=11515.msg109840#msg109840

 

this drive had not been precleared before being put into service (I started preclearing drives a bit after installing this trouble maker).  This one drive is the only WD drive that has ever given me problems while in service. Once I had finally identified this drive and removed it from the array, I precleared it and that appeared to fix the problem (probably the re-writing and verifying caused the drive to finally remap the poor sectors), but I only use it for testing things these days.

 

Regards,

 

Stephen