Disk being cleared unnecessarily?

[sdamaged]

Hi,

 

I put a new 14TB disk into my server and precleared it whilst my array was doing a parity check.  The disk cleared, and then formatted. Once the parity check was complete, i stopped the array and added the newly cleared disk into the array.  It's now forced me into doing another clear, with no way for me to say "this has already been done", and it's going to take around 16 hours

 

Is this expected behaviour?

[JonathanM]

6 minutes ago, sdamaged said:

The disk cleared, and then formatted.

If you formatted the disk, it was no longer clear.

[sdamaged]

Lol, lesson learned for next time! Thanks

[jagame]

I have the same issue but I never formatted the drive. I had an old 8TB disk that took 51 hours to finish all 10 steps of the preclear. I then added the disk to my array and it started clearing again. It's been over 2 hours and I'm only at 20%. Is there a detailed explanation of the preclear process as well as what is evaluated when a disk is added because this seems pretty ridiculous. I thought I understood preclear was writing all zeros to the disk and wiping all partitions but if so, then why is it clearing it again? Is there a log file with the details of what it found and the actions unraid is taking? 

[JonathanM]

When a preclear is successfully completed, a special binary signature is written to the disk. If anything manipulates the bits on the drive and alters that signature, Unraid assumes the disk is not clear and goes through the clear action to ensure parity remains valid.

 

There are several possible reasons why the preclear doesn't carry over, but the bottom line is that preclear is NOT and has never been an official Unraid function, since clearing the drive doesn't keep the array from being used normally. It's simply a very thorough user authored test of the drive. Limetech is most likely not going to dedicate any resources to figuring out why preclear doesn't function as it has in the past.