Rebuild to larger drive - What is actually being written in "new" area?

[TDD]

Hi All.

 

Just curious and want to know...

 

I pulled an old 1TB drive and popped in a new 4TB to replace.  It is happily rebuilding the drive.

 

My question is...

 

My system is current bound by a 4TB parity drive.  All other drives are a mix of 1, 2, and 4TB models.  Now that I pulled the 1TB, just what exactly is being written to the remaining 75% of the drive?  The original 1TB is already written, and the system just parity stripes across the drives, so it is just zeroing the remainder?

 

It is not like there is new data being placed there, nor rebuilding a 4TB drive that is replacing a 4TB drive.

 

This process was started on a precleared disk as well.

 

Kev.

[Squid]

22 minutes ago, TDD said:

so it is just zeroing the remainder?

Yes.

 

Effectively it is rebuilding the entire 4tb, but the remainder after the 1tb is effectively all zeroes.  unRaid only utilizes the preclear signature when adding a new disk to the array.

[TDD]

VG - I thought so.  I assume there is no logic in place to cut off the rebuild past the drive's end?  Likely more work than is worth it I suspect.  

 

Kev.

[trurl]

7 minutes ago, TDD said:

VG - I thought so.  I assume there is no logic in place to cut off the rebuild past the drive's end?  Likely more work than is worth it I suspect.  

Probably just better to not make any assumptions about what is on the rest of the drive, or what should be there, so rebuilding the rest from parity is the best thing since it will preserve valid parity.