Hello everyone. New Unraid user here, probably asking a very basic question, but I would rather ask before I do something stupid.

 

I recently switched from Qnap to my own and Ireused the old drives. Two of the drives are showing "Reallocated sector count." Sucks, but great news, still under warranty so I got with Seagate, and they are sending new ones (exact same size). My question is this: Do I NEED to do a preclear before I install it. I know with a larger replacement drive you do not have to and honestly, I prob will but I want to know for sure. I have searched the forums; read the steps and I just want to make sure I read correctly. 

Preclear is NEVER required. It's purely a means to thoroughly test a drive, and optionally speed up the process if you are adding the drive to a NEW (not replacement) data slot in an already valid parity array. Unraid will automatically clear (not preclear) a drive assigned to an additional data slot, but if a valid preclear signature is found on the drive, Unraid will skip the clearing phase and immediately offer to format the new drive slot, saving several hours.

 

Rebuilding a drive always writes the emulated image to the entire capacity of the drive, regardless of the content of the drive, cleared or otherwise.

 

Reallocated sectors are not necessarily fatal, but depending on how many and if they are increasing it may be a sign of impending failure. A small number that doesn't increase over time is probably fine.

@JonathanM, Awesome, I thought that was what it was, just wanted to make sure. Also, good to know about the HDD status. It is under warranty and Seagate was more than willing to replace it so I would rather side with caution. I am probably going to Preclear I just wanted to make sure and know all my options.

Edited April 25, 20224 yr by dubbleup99