How many preclear passes?


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Do you guys use the preclar plugin, and if so, how many passes do you run before adding a new drive to the array?

 

In my Unraid I currently use six 10TB WB My Book, and the seventh is currently preclearing. I do two preclear passes before I shuck the drive, and then I do one pass after I installed the drive internally.

When I do the first preclear passes while the drive is still in the USB case I use a fan on top of the case for cooling, and the temperature stays below 35°C.

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I just do 2 passes while in the USB enclosure and leave it at that. Personally I don't see any reason to do more than that, but I guess it comes down entirely to your risk appetite. If the extra pass helps you sleep better at night then go for it!

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I use the preclear Docker and I try to get about 70+ hours on the hard drive.  My objective is to make sure that the HD is not going to fail because of infant mortality.  I do this for two reasons. 

 

1-- I test as soon as I get the disk.  I only purchase from vendors who provide for 'no-hassle' returns with in X days of purchase for DOA drives.  This means I don't have to deal with warranty issues with the manufacturer.

 

2-- I have a policy that I want a cold spare ready for installation if a disk 'red-balls'.  I pull the disk and replace with the cold spare and start the rebuild.  When that is complete and the server is working normally again, I can take my time to test and determine what to do with 'defective' disk...

 

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14 hours ago, Frank1940 said:

I use the preclear Docker and I try to get about 70+ hours on the hard drive.  My objective is to make sure that the HD is not going to fail because of infant mortality.  I do this for two reasons. 

 

1-- I test as soon as I get the disk.  I only purchase from vendors who provide for 'no-hassle' returns with in X days of purchase for DOA drives.  This means I don't have to deal with warranty issues with the manufacturer.

 

2-- I have a policy that I want a cold spare ready for installation if a disk 'red-balls'.  I pull the disk and replace with the cold spare and start the rebuild.  When that is complete and the server is working normally again, I can take my time to test and determine what to do with 'defective' disk...

 

 

Ok, that seems like a smart strategy. 

 

For my 10TB WD My Book it takes about 56 hours for each pass (pre-read, zeroing and post-read), so two passes might be more than enough.

Ana I have also thought about having a cold spare at hand, maybe not a bad idea.

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