I was adding a drive to the array and forgot to do preclear on it. Surely enough unRaid took some time to do the job and finally my array is up. I have not formatted the drive yet and after reading some posts about advantage of preclear I decided to unmount the drive and do preclear first. Will unmounting of non-formatted drive invalidate parity of my array?

I'm sorry if this topic was already discussed, but I couldn't find the answer...

un-mounting it will not, but clearing it will.

 

To run another pre-clear you must un-assign it and start the array with it un-assigned.

Then, you can re-assign it after the pre-clear, or set a new initial configuration without it assigned and calculate a new parity without it.

 

Or, you can just leave it as it is and run several non-correcting parity checks (that will read it in its entirety)

to perform a non-correcting parity check on an older version of unRAID you must do it on the command line, or on the unMENU add-on page.

 

To start one from the command line type:

 

/root/mdcmd check NOCORRECT

(capitalization is important, enter as in the above line)

Thanks Joe for your response. I just wanted to avoid parity recalculation - it is relatively small drive and I didn't want to recalculate parity since I recently did it.

What I don't get is that why precleared disk would break parity? I added several precleared drives to my array and parity never needed to be recalculated (and it makes sense to me since disk with all zeros shouldn't affect existing parity values)...

 

un-mounting it will not, but clearing it will.

 

To run another pre-clear you must un-assign it and start the array with it un-assigned.

Then, you can re-assign it after the pre-clear, or set a new initial configuration without it assigned and calculate a new parity without it.

 

Or, you can just leave it as it is and run several non-correcting parity checks (that will read it in its entirety)

to perform a non-correcting parity check on an older version of unRAID you must do it on the command line, or on the unMENU add-on page.

 

To start one from the command line type:

 

/root/mdcmd check NOCORRECT

(capitalization is important, enter as in the above line)

Thanks Joe for your response. I just wanted to avoid parity recalculation - it is relatively small drive and I didn't want to recalculate parity since I recently did it.

What I don't get is that why precleared disk would break parity? I added several precleared drives to my array and parity never needed to be recalculated (and it makes sense to me since disk with all zeros shouldn't affect existing parity values)...

 

un-mounting it will not, but clearing it will.

 

To run another pre-clear you must un-assign it and start the array with it un-assigned.

Then, you can re-assign it after the pre-clear, or set a new initial configuration without it assigned and calculate a new parity without it.

 

Or, you can just leave it as it is and run several non-correcting parity checks (that will read it in its entirety)

to perform a non-correcting parity check on an older version of unRAID you must do it on the command line, or on the unMENU add-on page.

 

To start one from the command line type:

 

/root/mdcmd check NOCORRECT

(capitalization is important, enter as in the above line)

If you've not yet formatted it, you should be OK as far as parity goes.  However, it currently does not have a pre-clear signature.  (That was changed once you assigned it to the array)

 

I really do not know how the array will react when you un-assign it, and then re-assign it.  Odds are it will do just fine.  It will want to re-construct it, that is for certain.

 

Joe L.

I managed to screw up my array anyways since I didn't realize that beta 14 doesn't fully support M1015 card which I installed. What is recommendation these days - downgrade to 12a or there are chances that the bug with spin down/up will be fixed in next beta?