During the upgrade process, when passing the size of the previous disk, just write zeroes.  There's no point continuing to read from the array to calculate the contents are zero, or am I missing something?

I'm not sure if it uses parity to build the rest of the disk or not. If so, it's probably because it's just simpler and safer to not make any assumptions about the current contents of parity in those areas. If the bits beyond the previous size are consistent with parity then everything is fine since none of those bits could have been part of the filesystem.

It works. Just be patient. 

In answer to trurl, yes it does use parity to rebuild the rest of the disk.  It's not that simple when you live in a climate where peak daytime temperatures reach mid 40'sC but night time is more than 25C cooler, anything that takes more than 16 hours is a major problem.

 

It's one of the reasons why I asked for the parity check to be paused and restarted.

Edited April 12, 20179 yr by Brucey7