My system has 12 drive slots with 2TB drives stored in nine of them.  The array consist of the frist 6 drives with the remaining 3 being hot spares. The three hot spares were precleared some time ago.  I am running 5.0 RC5 with simple features. I am getting low on sapce so I desired to add one of the spare drives into the array. 

 

I stopped the array and brought one of the spare precleared drives into the array.  I then restarted the array.  The array started and indicated that the just added drive needed to be formatted.  I started the format process which is going on now.

 

Question:  Since I precleared the drive shouldn't it have been recognized as formatted and skipped the format step bringing the drive right into the array?  I may have precleared the drive under unRaid version 4.7, would that have made a difference?

 

The format process took about 5-10 minutes and everything looks okay.  I am just curious.  I thought format involved a preclear, but I guess not.  Any information would be appreciated.

Pre-clear does not create the file system.